Adding upstream version 1.1.0.upstream/1.1.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4718 insertions, 0 deletions

diff --git a/src/bpf_helper_defs.h b/src/bpf_helper_defs.h
new file mode 100644
index 0000000..9bcaca1
--- /dev/null
+++ b/src/bpf_helper_defs.h
@@ -0,0 +1,4718 @@
+/* This is auto-generated file. See bpf_doc.py for details. */
+
+/* Forward declarations of BPF structs */
+struct bpf_fib_lookup;
+struct bpf_sk_lookup;
+struct bpf_perf_event_data;
+struct bpf_perf_event_value;
+struct bpf_pidns_info;
+struct bpf_redir_neigh;
+struct bpf_sock;
+struct bpf_sock_addr;
+struct bpf_sock_ops;
+struct bpf_sock_tuple;
+struct bpf_spin_lock;
+struct bpf_sysctl;
+struct bpf_tcp_sock;
+struct bpf_tunnel_key;
+struct bpf_xfrm_state;
+struct linux_binprm;
+struct pt_regs;
+struct sk_reuseport_md;
+struct sockaddr;
+struct tcphdr;
+struct seq_file;
+struct tcp6_sock;
+struct tcp_sock;
+struct tcp_timewait_sock;
+struct tcp_request_sock;
+struct udp6_sock;
+struct unix_sock;
+struct task_struct;
+struct cgroup;
+struct __sk_buff;
+struct sk_msg_md;
+struct xdp_md;
+struct path;
+struct btf_ptr;
+struct inode;
+struct socket;
+struct file;
+struct bpf_timer;
+struct mptcp_sock;
+struct bpf_dynptr;
+struct iphdr;
+struct ipv6hdr;
+
+/*
+ * bpf_map_lookup_elem
+ *
+ * 	Perform a lookup in *map* for an entry associated to *key*.
+ *
+ * Returns
+ * 	Map value associated to *key*, or **NULL** if no entry was
+ * 	found.
+ */
+static void *(*bpf_map_lookup_elem)(void *map, const void *key) = (void *) 1;
+
+/*
+ * bpf_map_update_elem
+ *
+ * 	Add or update the value of the entry associated to *key* in
+ * 	*map* with *value*. *flags* is one of:
+ *
+ * 	**BPF_NOEXIST**
+ * 		The entry for *key* must not exist in the map.
+ * 	**BPF_EXIST**
+ * 		The entry for *key* must already exist in the map.
+ * 	**BPF_ANY**
+ * 		No condition on the existence of the entry for *key*.
+ *
+ * 	Flag value **BPF_NOEXIST** cannot be used for maps of types
+ * 	**BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY**  (all
+ * 	elements always exist), the helper would return an error.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_map_update_elem)(void *map, const void *key, const void *value, __u64 flags) = (void *) 2;
+
+/*
+ * bpf_map_delete_elem
+ *
+ * 	Delete entry with *key* from *map*.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_map_delete_elem)(void *map, const void *key) = (void *) 3;
+
+/*
+ * bpf_probe_read
+ *
+ * 	For tracing programs, safely attempt to read *size* bytes from
+ * 	kernel space address *unsafe_ptr* and store the data in *dst*.
+ *
+ * 	Generally, use **bpf_probe_read_user**\ () or
+ * 	**bpf_probe_read_kernel**\ () instead.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_probe_read)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 4;
+
+/*
+ * bpf_ktime_get_ns
+ *
+ * 	Return the time elapsed since system boot, in nanoseconds.
+ * 	Does not include time the system was suspended.
+ * 	See: **clock_gettime**\ (**CLOCK_MONOTONIC**)
+ *
+ * Returns
+ * 	Current *ktime*.
+ */
+static __u64 (*bpf_ktime_get_ns)(void) = (void *) 5;
+
+/*
+ * bpf_trace_printk
+ *
+ * 	This helper is a "printk()-like" facility for debugging. It
+ * 	prints a message defined by format *fmt* (of size *fmt_size*)
+ * 	to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
+ * 	available. It can take up to three additional **u64**
+ * 	arguments (as an eBPF helpers, the total number of arguments is
+ * 	limited to five).
+ *
+ * 	Each time the helper is called, it appends a line to the trace.
+ * 	Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
+ * 	open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
+ * 	The format of the trace is customizable, and the exact output
+ * 	one will get depends on the options set in
+ * 	*\/sys/kernel/debug/tracing/trace_options* (see also the
+ * 	*README* file under the same directory). However, it usually
+ * 	defaults to something like:
+ *
+ * 	::
+ *
+ * 		telnet-470   [001] .N.. 419421.045894: 0x00000001: <formatted msg>
+ *
+ * 	In the above:
+ *
+ * 		* ``telnet`` is the name of the current task.
+ * 		* ``470`` is the PID of the current task.
+ * 		* ``001`` is the CPU number on which the task is
+ * 		  running.
+ * 		* In ``.N..``, each character refers to a set of
+ * 		  options (whether irqs are enabled, scheduling
+ * 		  options, whether hard/softirqs are running, level of
+ * 		  preempt_disabled respectively). **N** means that
+ * 		  **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
+ * 		  are set.
+ * 		* ``419421.045894`` is a timestamp.
+ * 		* ``0x00000001`` is a fake value used by BPF for the
+ * 		  instruction pointer register.
+ * 		* ``<formatted msg>`` is the message formatted with
+ * 		  *fmt*.
+ *
+ * 	The conversion specifiers supported by *fmt* are similar, but
+ * 	more limited than for printk(). They are **%d**, **%i**,
+ * 	**%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
+ * 	**%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
+ * 	of field, padding with zeroes, etc.) is available, and the
+ * 	helper will return **-EINVAL** (but print nothing) if it
+ * 	encounters an unknown specifier.
+ *
+ * 	Also, note that **bpf_trace_printk**\ () is slow, and should
+ * 	only be used for debugging purposes. For this reason, a notice
+ * 	block (spanning several lines) is printed to kernel logs and
+ * 	states that the helper should not be used "for production use"
+ * 	the first time this helper is used (or more precisely, when
+ * 	**trace_printk**\ () buffers are allocated). For passing values
+ * 	to user space, perf events should be preferred.
+ *
+ * Returns
+ * 	The number of bytes written to the buffer, or a negative error
+ * 	in case of failure.
+ */
+static long (*bpf_trace_printk)(const char *fmt, __u32 fmt_size, ...) = (void *) 6;
+
+/*
+ * bpf_get_prandom_u32
+ *
+ * 	Get a pseudo-random number.
+ *
+ * 	From a security point of view, this helper uses its own
+ * 	pseudo-random internal state, and cannot be used to infer the
+ * 	seed of other random functions in the kernel. However, it is
+ * 	essential to note that the generator used by the helper is not
+ * 	cryptographically secure.
+ *
+ * Returns
+ * 	A random 32-bit unsigned value.
+ */
+static __u32 (*bpf_get_prandom_u32)(void) = (void *) 7;
+
+/*
+ * bpf_get_smp_processor_id
+ *
+ * 	Get the SMP (symmetric multiprocessing) processor id. Note that
+ * 	all programs run with migration disabled, which means that the
+ * 	SMP processor id is stable during all the execution of the
+ * 	program.
+ *
+ * Returns
+ * 	The SMP id of the processor running the program.
+ */
+static __u32 (*bpf_get_smp_processor_id)(void) = (void *) 8;
+
+/*
+ * bpf_skb_store_bytes
+ *
+ * 	Store *len* bytes from address *from* into the packet
+ * 	associated to *skb*, at *offset*. *flags* are a combination of
+ * 	**BPF_F_RECOMPUTE_CSUM** (automatically recompute the
+ * 	checksum for the packet after storing the bytes) and
+ * 	**BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
+ * 	**->swhash** and *skb*\ **->l4hash** to 0).
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_store_bytes)(struct __sk_buff *skb, __u32 offset, const void *from, __u32 len, __u64 flags) = (void *) 9;
+
+/*
+ * bpf_l3_csum_replace
+ *
+ * 	Recompute the layer 3 (e.g. IP) checksum for the packet
+ * 	associated to *skb*. Computation is incremental, so the helper
+ * 	must know the former value of the header field that was
+ * 	modified (*from*), the new value of this field (*to*), and the
+ * 	number of bytes (2 or 4) for this field, stored in *size*.
+ * 	Alternatively, it is possible to store the difference between
+ * 	the previous and the new values of the header field in *to*, by
+ * 	setting *from* and *size* to 0. For both methods, *offset*
+ * 	indicates the location of the IP checksum within the packet.
+ *
+ * 	This helper works in combination with **bpf_csum_diff**\ (),
+ * 	which does not update the checksum in-place, but offers more
+ * 	flexibility and can handle sizes larger than 2 or 4 for the
+ * 	checksum to update.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_l3_csum_replace)(struct __sk_buff *skb, __u32 offset, __u64 from, __u64 to, __u64 size) = (void *) 10;
+
+/*
+ * bpf_l4_csum_replace
+ *
+ * 	Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
+ * 	packet associated to *skb*. Computation is incremental, so the
+ * 	helper must know the former value of the header field that was
+ * 	modified (*from*), the new value of this field (*to*), and the
+ * 	number of bytes (2 or 4) for this field, stored on the lowest
+ * 	four bits of *flags*. Alternatively, it is possible to store
+ * 	the difference between the previous and the new values of the
+ * 	header field in *to*, by setting *from* and the four lowest
+ * 	bits of *flags* to 0. For both methods, *offset* indicates the
+ * 	location of the IP checksum within the packet. In addition to
+ * 	the size of the field, *flags* can be added (bitwise OR) actual
+ * 	flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
+ * 	untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
+ * 	for updates resulting in a null checksum the value is set to
+ * 	**CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
+ * 	the checksum is to be computed against a pseudo-header.
+ *
+ * 	This helper works in combination with **bpf_csum_diff**\ (),
+ * 	which does not update the checksum in-place, but offers more
+ * 	flexibility and can handle sizes larger than 2 or 4 for the
+ * 	checksum to update.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_l4_csum_replace)(struct __sk_buff *skb, __u32 offset, __u64 from, __u64 to, __u64 flags) = (void *) 11;
+
+/*
+ * bpf_tail_call
+ *
+ * 	This special helper is used to trigger a "tail call", or in
+ * 	other words, to jump into another eBPF program. The same stack
+ * 	frame is used (but values on stack and in registers for the
+ * 	caller are not accessible to the callee). This mechanism allows
+ * 	for program chaining, either for raising the maximum number of
+ * 	available eBPF instructions, or to execute given programs in
+ * 	conditional blocks. For security reasons, there is an upper
+ * 	limit to the number of successive tail calls that can be
+ * 	performed.
+ *
+ * 	Upon call of this helper, the program attempts to jump into a
+ * 	program referenced at index *index* in *prog_array_map*, a
+ * 	special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
+ * 	*ctx*, a pointer to the context.
+ *
+ * 	If the call succeeds, the kernel immediately runs the first
+ * 	instruction of the new program. This is not a function call,
+ * 	and it never returns to the previous program. If the call
+ * 	fails, then the helper has no effect, and the caller continues
+ * 	to run its subsequent instructions. A call can fail if the
+ * 	destination program for the jump does not exist (i.e. *index*
+ * 	is superior to the number of entries in *prog_array_map*), or
+ * 	if the maximum number of tail calls has been reached for this
+ * 	chain of programs. This limit is defined in the kernel by the
+ * 	macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
+ * 	which is currently set to 33.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_tail_call)(void *ctx, void *prog_array_map, __u32 index) = (void *) 12;
+
+/*
+ * bpf_clone_redirect
+ *
+ * 	Clone and redirect the packet associated to *skb* to another
+ * 	net device of index *ifindex*. Both ingress and egress
+ * 	interfaces can be used for redirection. The **BPF_F_INGRESS**
+ * 	value in *flags* is used to make the distinction (ingress path
+ * 	is selected if the flag is present, egress path otherwise).
+ * 	This is the only flag supported for now.
+ *
+ * 	In comparison with **bpf_redirect**\ () helper,
+ * 	**bpf_clone_redirect**\ () has the associated cost of
+ * 	duplicating the packet buffer, but this can be executed out of
+ * 	the eBPF program. Conversely, **bpf_redirect**\ () is more
+ * 	efficient, but it is handled through an action code where the
+ * 	redirection happens only after the eBPF program has returned.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_clone_redirect)(struct __sk_buff *skb, __u32 ifindex, __u64 flags) = (void *) 13;
+
+/*
+ * bpf_get_current_pid_tgid
+ *
+ * 	Get the current pid and tgid.
+ *
+ * Returns
+ * 	A 64-bit integer containing the current tgid and pid, and
+ * 	created as such:
+ * 	*current_task*\ **->tgid << 32 \|**
+ * 	*current_task*\ **->pid**.
+ */
+static __u64 (*bpf_get_current_pid_tgid)(void) = (void *) 14;
+
+/*
+ * bpf_get_current_uid_gid
+ *
+ * 	Get the current uid and gid.
+ *
+ * Returns
+ * 	A 64-bit integer containing the current GID and UID, and
+ * 	created as such: *current_gid* **<< 32 \|** *current_uid*.
+ */
+static __u64 (*bpf_get_current_uid_gid)(void) = (void *) 15;
+
+/*
+ * bpf_get_current_comm
+ *
+ * 	Copy the **comm** attribute of the current task into *buf* of
+ * 	*size_of_buf*. The **comm** attribute contains the name of
+ * 	the executable (excluding the path) for the current task. The
+ * 	*size_of_buf* must be strictly positive. On success, the
+ * 	helper makes sure that the *buf* is NUL-terminated. On failure,
+ * 	it is filled with zeroes.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_get_current_comm)(void *buf, __u32 size_of_buf) = (void *) 16;
+
+/*
+ * bpf_get_cgroup_classid
+ *
+ * 	Retrieve the classid for the current task, i.e. for the net_cls
+ * 	cgroup to which *skb* belongs.
+ *
+ * 	This helper can be used on TC egress path, but not on ingress.
+ *
+ * 	The net_cls cgroup provides an interface to tag network packets
+ * 	based on a user-provided identifier for all traffic coming from
+ * 	the tasks belonging to the related cgroup. See also the related
+ * 	kernel documentation, available from the Linux sources in file
+ * 	*Documentation/admin-guide/cgroup-v1/net_cls.rst*.
+ *
+ * 	The Linux kernel has two versions for cgroups: there are
+ * 	cgroups v1 and cgroups v2. Both are available to users, who can
+ * 	use a mixture of them, but note that the net_cls cgroup is for
+ * 	cgroup v1 only. This makes it incompatible with BPF programs
+ * 	run on cgroups, which is a cgroup-v2-only feature (a socket can
+ * 	only hold data for one version of cgroups at a time).
+ *
+ * 	This helper is only available is the kernel was compiled with
+ * 	the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
+ * 	"**y**" or to "**m**".
+ *
+ * Returns
+ * 	The classid, or 0 for the default unconfigured classid.
+ */
+static __u32 (*bpf_get_cgroup_classid)(struct __sk_buff *skb) = (void *) 17;
+
+/*
+ * bpf_skb_vlan_push
+ *
+ * 	Push a *vlan_tci* (VLAN tag control information) of protocol
+ * 	*vlan_proto* to the packet associated to *skb*, then update
+ * 	the checksum. Note that if *vlan_proto* is different from
+ * 	**ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
+ * 	be **ETH_P_8021Q**.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_vlan_push)(struct __sk_buff *skb, __be16 vlan_proto, __u16 vlan_tci) = (void *) 18;
+
+/*
+ * bpf_skb_vlan_pop
+ *
+ * 	Pop a VLAN header from the packet associated to *skb*.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_vlan_pop)(struct __sk_buff *skb) = (void *) 19;
+
+/*
+ * bpf_skb_get_tunnel_key
+ *
+ * 	Get tunnel metadata. This helper takes a pointer *key* to an
+ * 	empty **struct bpf_tunnel_key** of **size**, that will be
+ * 	filled with tunnel metadata for the packet associated to *skb*.
+ * 	The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
+ * 	indicates that the tunnel is based on IPv6 protocol instead of
+ * 	IPv4.
+ *
+ * 	The **struct bpf_tunnel_key** is an object that generalizes the
+ * 	principal parameters used by various tunneling protocols into a
+ * 	single struct. This way, it can be used to easily make a
+ * 	decision based on the contents of the encapsulation header,
+ * 	"summarized" in this struct. In particular, it holds the IP
+ * 	address of the remote end (IPv4 or IPv6, depending on the case)
+ * 	in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
+ * 	this struct exposes the *key*\ **->tunnel_id**, which is
+ * 	generally mapped to a VNI (Virtual Network Identifier), making
+ * 	it programmable together with the **bpf_skb_set_tunnel_key**\
+ * 	() helper.
+ *
+ * 	Let's imagine that the following code is part of a program
+ * 	attached to the TC ingress interface, on one end of a GRE
+ * 	tunnel, and is supposed to filter out all messages coming from
+ * 	remote ends with IPv4 address other than 10.0.0.1:
+ *
+ * 	::
+ *
+ * 		int ret;
+ * 		struct bpf_tunnel_key key = {};
+ *
+ * 		ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
+ * 		if (ret < 0)
+ * 			return TC_ACT_SHOT;	// drop packet
+ *
+ * 		if (key.remote_ipv4 != 0x0a000001)
+ * 			return TC_ACT_SHOT;	// drop packet
+ *
+ * 		return TC_ACT_OK;		// accept packet
+ *
+ * 	This interface can also be used with all encapsulation devices
+ * 	that can operate in "collect metadata" mode: instead of having
+ * 	one network device per specific configuration, the "collect
+ * 	metadata" mode only requires a single device where the
+ * 	configuration can be extracted from this helper.
+ *
+ * 	This can be used together with various tunnels such as VXLan,
+ * 	Geneve, GRE or IP in IP (IPIP).
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_get_tunnel_key)(struct __sk_buff *skb, struct bpf_tunnel_key *key, __u32 size, __u64 flags) = (void *) 20;
+
+/*
+ * bpf_skb_set_tunnel_key
+ *
+ * 	Populate tunnel metadata for packet associated to *skb.* The
+ * 	tunnel metadata is set to the contents of *key*, of *size*. The
+ * 	*flags* can be set to a combination of the following values:
+ *
+ * 	**BPF_F_TUNINFO_IPV6**
+ * 		Indicate that the tunnel is based on IPv6 protocol
+ * 		instead of IPv4.
+ * 	**BPF_F_ZERO_CSUM_TX**
+ * 		For IPv4 packets, add a flag to tunnel metadata
+ * 		indicating that checksum computation should be skipped
+ * 		and checksum set to zeroes.
+ * 	**BPF_F_DONT_FRAGMENT**
+ * 		Add a flag to tunnel metadata indicating that the
+ * 		packet should not be fragmented.
+ * 	**BPF_F_SEQ_NUMBER**
+ * 		Add a flag to tunnel metadata indicating that a
+ * 		sequence number should be added to tunnel header before
+ * 		sending the packet. This flag was added for GRE
+ * 		encapsulation, but might be used with other protocols
+ * 		as well in the future.
+ * 	**BPF_F_NO_TUNNEL_KEY**
+ * 		Add a flag to tunnel metadata indicating that no tunnel
+ * 		key should be set in the resulting tunnel header.
+ *
+ * 	Here is a typical usage on the transmit path:
+ *
+ * 	::
+ *
+ * 		struct bpf_tunnel_key key;
+ * 		     populate key ...
+ * 		bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
+ * 		bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
+ *
+ * 	See also the description of the **bpf_skb_get_tunnel_key**\ ()
+ * 	helper for additional information.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_set_tunnel_key)(struct __sk_buff *skb, struct bpf_tunnel_key *key, __u32 size, __u64 flags) = (void *) 21;
+
+/*
+ * bpf_perf_event_read
+ *
+ * 	Read the value of a perf event counter. This helper relies on a
+ * 	*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
+ * 	the perf event counter is selected when *map* is updated with
+ * 	perf event file descriptors. The *map* is an array whose size
+ * 	is the number of available CPUs, and each cell contains a value
+ * 	relative to one CPU. The value to retrieve is indicated by
+ * 	*flags*, that contains the index of the CPU to look up, masked
+ * 	with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
+ * 	**BPF_F_CURRENT_CPU** to indicate that the value for the
+ * 	current CPU should be retrieved.
+ *
+ * 	Note that before Linux 4.13, only hardware perf event can be
+ * 	retrieved.
+ *
+ * 	Also, be aware that the newer helper
+ * 	**bpf_perf_event_read_value**\ () is recommended over
+ * 	**bpf_perf_event_read**\ () in general. The latter has some ABI
+ * 	quirks where error and counter value are used as a return code
+ * 	(which is wrong to do since ranges may overlap). This issue is
+ * 	fixed with **bpf_perf_event_read_value**\ (), which at the same
+ * 	time provides more features over the **bpf_perf_event_read**\
+ * 	() interface. Please refer to the description of
+ * 	**bpf_perf_event_read_value**\ () for details.
+ *
+ * Returns
+ * 	The value of the perf event counter read from the map, or a
+ * 	negative error code in case of failure.
+ */
+static __u64 (*bpf_perf_event_read)(void *map, __u64 flags) = (void *) 22;
+
+/*
+ * bpf_redirect
+ *
+ * 	Redirect the packet to another net device of index *ifindex*.
+ * 	This helper is somewhat similar to **bpf_clone_redirect**\
+ * 	(), except that the packet is not cloned, which provides
+ * 	increased performance.
+ *
+ * 	Except for XDP, both ingress and egress interfaces can be used
+ * 	for redirection. The **BPF_F_INGRESS** value in *flags* is used
+ * 	to make the distinction (ingress path is selected if the flag
+ * 	is present, egress path otherwise). Currently, XDP only
+ * 	supports redirection to the egress interface, and accepts no
+ * 	flag at all.
+ *
+ * 	The same effect can also be attained with the more generic
+ * 	**bpf_redirect_map**\ (), which uses a BPF map to store the
+ * 	redirect target instead of providing it directly to the helper.
+ *
+ * Returns
+ * 	For XDP, the helper returns **XDP_REDIRECT** on success or
+ * 	**XDP_ABORTED** on error. For other program types, the values
+ * 	are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
+ * 	error.
+ */
+static long (*bpf_redirect)(__u32 ifindex, __u64 flags) = (void *) 23;
+
+/*
+ * bpf_get_route_realm
+ *
+ * 	Retrieve the realm or the route, that is to say the
+ * 	**tclassid** field of the destination for the *skb*. The
+ * 	identifier retrieved is a user-provided tag, similar to the
+ * 	one used with the net_cls cgroup (see description for
+ * 	**bpf_get_cgroup_classid**\ () helper), but here this tag is
+ * 	held by a route (a destination entry), not by a task.
+ *
+ * 	Retrieving this identifier works with the clsact TC egress hook
+ * 	(see also **tc-bpf(8)**), or alternatively on conventional
+ * 	classful egress qdiscs, but not on TC ingress path. In case of
+ * 	clsact TC egress hook, this has the advantage that, internally,
+ * 	the destination entry has not been dropped yet in the transmit
+ * 	path. Therefore, the destination entry does not need to be
+ * 	artificially held via **netif_keep_dst**\ () for a classful
+ * 	qdisc until the *skb* is freed.
+ *
+ * 	This helper is available only if the kernel was compiled with
+ * 	**CONFIG_IP_ROUTE_CLASSID** configuration option.
+ *
+ * Returns
+ * 	The realm of the route for the packet associated to *skb*, or 0
+ * 	if none was found.
+ */
+static __u32 (*bpf_get_route_realm)(struct __sk_buff *skb) = (void *) 24;
+
+/*
+ * bpf_perf_event_output
+ *
+ * 	Write raw *data* blob into a special BPF perf event held by
+ * 	*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
+ * 	event must have the following attributes: **PERF_SAMPLE_RAW**
+ * 	as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
+ * 	**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
+ *
+ * 	The *flags* are used to indicate the index in *map* for which
+ * 	the value must be put, masked with **BPF_F_INDEX_MASK**.
+ * 	Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
+ * 	to indicate that the index of the current CPU core should be
+ * 	used.
+ *
+ * 	The value to write, of *size*, is passed through eBPF stack and
+ * 	pointed by *data*.
+ *
+ * 	The context of the program *ctx* needs also be passed to the
+ * 	helper.
+ *
+ * 	On user space, a program willing to read the values needs to
+ * 	call **perf_event_open**\ () on the perf event (either for
+ * 	one or for all CPUs) and to store the file descriptor into the
+ * 	*map*. This must be done before the eBPF program can send data
+ * 	into it. An example is available in file
+ * 	*samples/bpf/trace_output_user.c* in the Linux kernel source
+ * 	tree (the eBPF program counterpart is in
+ * 	*samples/bpf/trace_output_kern.c*).
+ *
+ * 	**bpf_perf_event_output**\ () achieves better performance
+ * 	than **bpf_trace_printk**\ () for sharing data with user
+ * 	space, and is much better suitable for streaming data from eBPF
+ * 	programs.
+ *
+ * 	Note that this helper is not restricted to tracing use cases
+ * 	and can be used with programs attached to TC or XDP as well,
+ * 	where it allows for passing data to user space listeners. Data
+ * 	can be:
+ *
+ * 	* Only custom structs,
+ * 	* Only the packet payload, or
+ * 	* A combination of both.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_perf_event_output)(void *ctx, void *map, __u64 flags, void *data, __u64 size) = (void *) 25;
+
+/*
+ * bpf_skb_load_bytes
+ *
+ * 	This helper was provided as an easy way to load data from a
+ * 	packet. It can be used to load *len* bytes from *offset* from
+ * 	the packet associated to *skb*, into the buffer pointed by
+ * 	*to*.
+ *
+ * 	Since Linux 4.7, usage of this helper has mostly been replaced
+ * 	by "direct packet access", enabling packet data to be
+ * 	manipulated with *skb*\ **->data** and *skb*\ **->data_end**
+ * 	pointing respectively to the first byte of packet data and to
+ * 	the byte after the last byte of packet data. However, it
+ * 	remains useful if one wishes to read large quantities of data
+ * 	at once from a packet into the eBPF stack.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_load_bytes)(const void *skb, __u32 offset, void *to, __u32 len) = (void *) 26;
+
+/*
+ * bpf_get_stackid
+ *
+ * 	Walk a user or a kernel stack and return its id. To achieve
+ * 	this, the helper needs *ctx*, which is a pointer to the context
+ * 	on which the tracing program is executed, and a pointer to a
+ * 	*map* of type **BPF_MAP_TYPE_STACK_TRACE**.
+ *
+ * 	The last argument, *flags*, holds the number of stack frames to
+ * 	skip (from 0 to 255), masked with
+ * 	**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
+ * 	a combination of the following flags:
+ *
+ * 	**BPF_F_USER_STACK**
+ * 		Collect a user space stack instead of a kernel stack.
+ * 	**BPF_F_FAST_STACK_CMP**
+ * 		Compare stacks by hash only.
+ * 	**BPF_F_REUSE_STACKID**
+ * 		If two different stacks hash into the same *stackid*,
+ * 		discard the old one.
+ *
+ * 	The stack id retrieved is a 32 bit long integer handle which
+ * 	can be further combined with other data (including other stack
+ * 	ids) and used as a key into maps. This can be useful for
+ * 	generating a variety of graphs (such as flame graphs or off-cpu
+ * 	graphs).
+ *
+ * 	For walking a stack, this helper is an improvement over
+ * 	**bpf_probe_read**\ (), which can be used with unrolled loops
+ * 	but is not efficient and consumes a lot of eBPF instructions.
+ * 	Instead, **bpf_get_stackid**\ () can collect up to
+ * 	**PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
+ * 	this limit can be controlled with the **sysctl** program, and
+ * 	that it should be manually increased in order to profile long
+ * 	user stacks (such as stacks for Java programs). To do so, use:
+ *
+ * 	::
+ *
+ * 		# sysctl kernel.perf_event_max_stack=<new value>
+ *
+ * Returns
+ * 	The positive or null stack id on success, or a negative error
+ * 	in case of failure.
+ */
+static long (*bpf_get_stackid)(void *ctx, void *map, __u64 flags) = (void *) 27;
+
+/*
+ * bpf_csum_diff
+ *
+ * 	Compute a checksum difference, from the raw buffer pointed by
+ * 	*from*, of length *from_size* (that must be a multiple of 4),
+ * 	towards the raw buffer pointed by *to*, of size *to_size*
+ * 	(same remark). An optional *seed* can be added to the value
+ * 	(this can be cascaded, the seed may come from a previous call
+ * 	to the helper).
+ *
+ * 	This is flexible enough to be used in several ways:
+ *
+ * 	* With *from_size* == 0, *to_size* > 0 and *seed* set to
+ * 	  checksum, it can be used when pushing new data.
+ * 	* With *from_size* > 0, *to_size* == 0 and *seed* set to
+ * 	  checksum, it can be used when removing data from a packet.
+ * 	* With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
+ * 	  can be used to compute a diff. Note that *from_size* and
+ * 	  *to_size* do not need to be equal.
+ *
+ * 	This helper can be used in combination with
+ * 	**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
+ * 	which one can feed in the difference computed with
+ * 	**bpf_csum_diff**\ ().
+ *
+ * Returns
+ * 	The checksum result, or a negative error code in case of
+ * 	failure.
+ */
+static __s64 (*bpf_csum_diff)(__be32 *from, __u32 from_size, __be32 *to, __u32 to_size, __wsum seed) = (void *) 28;
+
+/*
+ * bpf_skb_get_tunnel_opt
+ *
+ * 	Retrieve tunnel options metadata for the packet associated to
+ * 	*skb*, and store the raw tunnel option data to the buffer *opt*
+ * 	of *size*.
+ *
+ * 	This helper can be used with encapsulation devices that can
+ * 	operate in "collect metadata" mode (please refer to the related
+ * 	note in the description of **bpf_skb_get_tunnel_key**\ () for
+ * 	more details). A particular example where this can be used is
+ * 	in combination with the Geneve encapsulation protocol, where it
+ * 	allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
+ * 	and retrieving arbitrary TLVs (Type-Length-Value headers) from
+ * 	the eBPF program. This allows for full customization of these
+ * 	headers.
+ *
+ * Returns
+ * 	The size of the option data retrieved.
+ */
+static long (*bpf_skb_get_tunnel_opt)(struct __sk_buff *skb, void *opt, __u32 size) = (void *) 29;
+
+/*
+ * bpf_skb_set_tunnel_opt
+ *
+ * 	Set tunnel options metadata for the packet associated to *skb*
+ * 	to the option data contained in the raw buffer *opt* of *size*.
+ *
+ * 	See also the description of the **bpf_skb_get_tunnel_opt**\ ()
+ * 	helper for additional information.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_set_tunnel_opt)(struct __sk_buff *skb, void *opt, __u32 size) = (void *) 30;
+
+/*
+ * bpf_skb_change_proto
+ *
+ * 	Change the protocol of the *skb* to *proto*. Currently
+ * 	supported are transition from IPv4 to IPv6, and from IPv6 to
+ * 	IPv4. The helper takes care of the groundwork for the
+ * 	transition, including resizing the socket buffer. The eBPF
+ * 	program is expected to fill the new headers, if any, via
+ * 	**skb_store_bytes**\ () and to recompute the checksums with
+ * 	**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
+ * 	(). The main case for this helper is to perform NAT64
+ * 	operations out of an eBPF program.
+ *
+ * 	Internally, the GSO type is marked as dodgy so that headers are
+ * 	checked and segments are recalculated by the GSO/GRO engine.
+ * 	The size for GSO target is adapted as well.
+ *
+ * 	All values for *flags* are reserved for future usage, and must
+ * 	be left at zero.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_change_proto)(struct __sk_buff *skb, __be16 proto, __u64 flags) = (void *) 31;
+
+/*
+ * bpf_skb_change_type
+ *
+ * 	Change the packet type for the packet associated to *skb*. This
+ * 	comes down to setting *skb*\ **->pkt_type** to *type*, except
+ * 	the eBPF program does not have a write access to *skb*\
+ * 	**->pkt_type** beside this helper. Using a helper here allows
+ * 	for graceful handling of errors.
+ *
+ * 	The major use case is to change incoming *skb*s to
+ * 	**PACKET_HOST** in a programmatic way instead of having to
+ * 	recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
+ * 	example.
+ *
+ * 	Note that *type* only allows certain values. At this time, they
+ * 	are:
+ *
+ * 	**PACKET_HOST**
+ * 		Packet is for us.
+ * 	**PACKET_BROADCAST**
+ * 		Send packet to all.
+ * 	**PACKET_MULTICAST**
+ * 		Send packet to group.
+ * 	**PACKET_OTHERHOST**
+ * 		Send packet to someone else.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_change_type)(struct __sk_buff *skb, __u32 type) = (void *) 32;
+
+/*
+ * bpf_skb_under_cgroup
+ *
+ * 	Check whether *skb* is a descendant of the cgroup2 held by
+ * 	*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
+ *
+ * Returns
+ * 	The return value depends on the result of the test, and can be:
+ *
+ * 	* 0, if the *skb* failed the cgroup2 descendant test.
+ * 	* 1, if the *skb* succeeded the cgroup2 descendant test.
+ * 	* A negative error code, if an error occurred.
+ */
+static long (*bpf_skb_under_cgroup)(struct __sk_buff *skb, void *map, __u32 index) = (void *) 33;
+
+/*
+ * bpf_get_hash_recalc
+ *
+ * 	Retrieve the hash of the packet, *skb*\ **->hash**. If it is
+ * 	not set, in particular if the hash was cleared due to mangling,
+ * 	recompute this hash. Later accesses to the hash can be done
+ * 	directly with *skb*\ **->hash**.
+ *
+ * 	Calling **bpf_set_hash_invalid**\ (), changing a packet
+ * 	prototype with **bpf_skb_change_proto**\ (), or calling
+ * 	**bpf_skb_store_bytes**\ () with the
+ * 	**BPF_F_INVALIDATE_HASH** are actions susceptible to clear
+ * 	the hash and to trigger a new computation for the next call to
+ * 	**bpf_get_hash_recalc**\ ().
+ *
+ * Returns
+ * 	The 32-bit hash.
+ */
+static __u32 (*bpf_get_hash_recalc)(struct __sk_buff *skb) = (void *) 34;
+
+/*
+ * bpf_get_current_task
+ *
+ * 	Get the current task.
+ *
+ * Returns
+ * 	A pointer to the current task struct.
+ */
+static __u64 (*bpf_get_current_task)(void) = (void *) 35;
+
+/*
+ * bpf_probe_write_user
+ *
+ * 	Attempt in a safe way to write *len* bytes from the buffer
+ * 	*src* to *dst* in memory. It only works for threads that are in
+ * 	user context, and *dst* must be a valid user space address.
+ *
+ * 	This helper should not be used to implement any kind of
+ * 	security mechanism because of TOC-TOU attacks, but rather to
+ * 	debug, divert, and manipulate execution of semi-cooperative
+ * 	processes.
+ *
+ * 	Keep in mind that this feature is meant for experiments, and it
+ * 	has a risk of crashing the system and running programs.
+ * 	Therefore, when an eBPF program using this helper is attached,
+ * 	a warning including PID and process name is printed to kernel
+ * 	logs.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_probe_write_user)(void *dst, const void *src, __u32 len) = (void *) 36;
+
+/*
+ * bpf_current_task_under_cgroup
+ *
+ * 	Check whether the probe is being run is the context of a given
+ * 	subset of the cgroup2 hierarchy. The cgroup2 to test is held by
+ * 	*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
+ *
+ * Returns
+ * 	The return value depends on the result of the test, and can be:
+ *
+ * 	* 1, if current task belongs to the cgroup2.
+ * 	* 0, if current task does not belong to the cgroup2.
+ * 	* A negative error code, if an error occurred.
+ */
+static long (*bpf_current_task_under_cgroup)(void *map, __u32 index) = (void *) 37;
+
+/*
+ * bpf_skb_change_tail
+ *
+ * 	Resize (trim or grow) the packet associated to *skb* to the
+ * 	new *len*. The *flags* are reserved for future usage, and must
+ * 	be left at zero.
+ *
+ * 	The basic idea is that the helper performs the needed work to
+ * 	change the size of the packet, then the eBPF program rewrites
+ * 	the rest via helpers like **bpf_skb_store_bytes**\ (),
+ * 	**bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
+ * 	and others. This helper is a slow path utility intended for
+ * 	replies with control messages. And because it is targeted for
+ * 	slow path, the helper itself can afford to be slow: it
+ * 	implicitly linearizes, unclones and drops offloads from the
+ * 	*skb*.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_change_tail)(struct __sk_buff *skb, __u32 len, __u64 flags) = (void *) 38;
+
+/*
+ * bpf_skb_pull_data
+ *
+ * 	Pull in non-linear data in case the *skb* is non-linear and not
+ * 	all of *len* are part of the linear section. Make *len* bytes
+ * 	from *skb* readable and writable. If a zero value is passed for
+ * 	*len*, then all bytes in the linear part of *skb* will be made
+ * 	readable and writable.
+ *
+ * 	This helper is only needed for reading and writing with direct
+ * 	packet access.
+ *
+ * 	For direct packet access, testing that offsets to access
+ * 	are within packet boundaries (test on *skb*\ **->data_end**) is
+ * 	susceptible to fail if offsets are invalid, or if the requested
+ * 	data is in non-linear parts of the *skb*. On failure the
+ * 	program can just bail out, or in the case of a non-linear
+ * 	buffer, use a helper to make the data available. The
+ * 	**bpf_skb_load_bytes**\ () helper is a first solution to access
+ * 	the data. Another one consists in using **bpf_skb_pull_data**
+ * 	to pull in once the non-linear parts, then retesting and
+ * 	eventually access the data.
+ *
+ * 	At the same time, this also makes sure the *skb* is uncloned,
+ * 	which is a necessary condition for direct write. As this needs
+ * 	to be an invariant for the write part only, the verifier
+ * 	detects writes and adds a prologue that is calling
+ * 	**bpf_skb_pull_data()** to effectively unclone the *skb* from
+ * 	the very beginning in case it is indeed cloned.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_pull_data)(struct __sk_buff *skb, __u32 len) = (void *) 39;
+
+/*
+ * bpf_csum_update
+ *
+ * 	Add the checksum *csum* into *skb*\ **->csum** in case the
+ * 	driver has supplied a checksum for the entire packet into that
+ * 	field. Return an error otherwise. This helper is intended to be
+ * 	used in combination with **bpf_csum_diff**\ (), in particular
+ * 	when the checksum needs to be updated after data has been
+ * 	written into the packet through direct packet access.
+ *
+ * Returns
+ * 	The checksum on success, or a negative error code in case of
+ * 	failure.
+ */
+static __s64 (*bpf_csum_update)(struct __sk_buff *skb, __wsum csum) = (void *) 40;
+
+/*
+ * bpf_set_hash_invalid
+ *
+ * 	Invalidate the current *skb*\ **->hash**. It can be used after
+ * 	mangling on headers through direct packet access, in order to
+ * 	indicate that the hash is outdated and to trigger a
+ * 	recalculation the next time the kernel tries to access this
+ * 	hash or when the **bpf_get_hash_recalc**\ () helper is called.
+ *
+ * Returns
+ * 	void.
+ */
+static void (*bpf_set_hash_invalid)(struct __sk_buff *skb) = (void *) 41;
+
+/*
+ * bpf_get_numa_node_id
+ *
+ * 	Return the id of the current NUMA node. The primary use case
+ * 	for this helper is the selection of sockets for the local NUMA
+ * 	node, when the program is attached to sockets using the
+ * 	**SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
+ * 	but the helper is also available to other eBPF program types,
+ * 	similarly to **bpf_get_smp_processor_id**\ ().
+ *
+ * Returns
+ * 	The id of current NUMA node.
+ */
+static long (*bpf_get_numa_node_id)(void) = (void *) 42;
+
+/*
+ * bpf_skb_change_head
+ *
+ * 	Grows headroom of packet associated to *skb* and adjusts the
+ * 	offset of the MAC header accordingly, adding *len* bytes of
+ * 	space. It automatically extends and reallocates memory as
+ * 	required.
+ *
+ * 	This helper can be used on a layer 3 *skb* to push a MAC header
+ * 	for redirection into a layer 2 device.
+ *
+ * 	All values for *flags* are reserved for future usage, and must
+ * 	be left at zero.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_change_head)(struct __sk_buff *skb, __u32 len, __u64 flags) = (void *) 43;
+
+/*
+ * bpf_xdp_adjust_head
+ *
+ * 	Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
+ * 	it is possible to use a negative value for *delta*. This helper
+ * 	can be used to prepare the packet for pushing or popping
+ * 	headers.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_xdp_adjust_head)(struct xdp_md *xdp_md, int delta) = (void *) 44;
+
+/*
+ * bpf_probe_read_str
+ *
+ * 	Copy a NUL terminated string from an unsafe kernel address
+ * 	*unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for
+ * 	more details.
+ *
+ * 	Generally, use **bpf_probe_read_user_str**\ () or
+ * 	**bpf_probe_read_kernel_str**\ () instead.
+ *
+ * Returns
+ * 	On success, the strictly positive length of the string,
+ * 	including the trailing NUL character. On error, a negative
+ * 	value.
+ */
+static long (*bpf_probe_read_str)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 45;
+
+/*
+ * bpf_get_socket_cookie
+ *
+ * 	If the **struct sk_buff** pointed by *skb* has a known socket,
+ * 	retrieve the cookie (generated by the kernel) of this socket.
+ * 	If no cookie has been set yet, generate a new cookie. Once
+ * 	generated, the socket cookie remains stable for the life of the
+ * 	socket. This helper can be useful for monitoring per socket
+ * 	networking traffic statistics as it provides a global socket
+ * 	identifier that can be assumed unique.
+ *
+ * Returns
+ * 	A 8-byte long unique number on success, or 0 if the socket
+ * 	field is missing inside *skb*.
+ */
+static __u64 (*bpf_get_socket_cookie)(void *ctx) = (void *) 46;
+
+/*
+ * bpf_get_socket_uid
+ *
+ * 	Get the owner UID of the socked associated to *skb*.
+ *
+ * Returns
+ * 	The owner UID of the socket associated to *skb*. If the socket
+ * 	is **NULL**, or if it is not a full socket (i.e. if it is a
+ * 	time-wait or a request socket instead), **overflowuid** value
+ * 	is returned (note that **overflowuid** might also be the actual
+ * 	UID value for the socket).
+ */
+static __u32 (*bpf_get_socket_uid)(struct __sk_buff *skb) = (void *) 47;
+
+/*
+ * bpf_set_hash
+ *
+ * 	Set the full hash for *skb* (set the field *skb*\ **->hash**)
+ * 	to value *hash*.
+ *
+ * Returns
+ * 	0
+ */
+static long (*bpf_set_hash)(struct __sk_buff *skb, __u32 hash) = (void *) 48;
+
+/*
+ * bpf_setsockopt
+ *
+ * 	Emulate a call to **setsockopt()** on the socket associated to
+ * 	*bpf_socket*, which must be a full socket. The *level* at
+ * 	which the option resides and the name *optname* of the option
+ * 	must be specified, see **setsockopt(2)** for more information.
+ * 	The option value of length *optlen* is pointed by *optval*.
+ *
+ * 	*bpf_socket* should be one of the following:
+ *
+ * 	* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
+ * 	* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
+ * 	  and **BPF_CGROUP_INET6_CONNECT**.
+ *
+ * 	This helper actually implements a subset of **setsockopt()**.
+ * 	It supports the following *level*\ s:
+ *
+ * 	* **SOL_SOCKET**, which supports the following *optname*\ s:
+ * 	  **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
+ * 	  **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
+ * 	  **SO_BINDTODEVICE**, **SO_KEEPALIVE**, **SO_REUSEADDR**,
+ * 	  **SO_REUSEPORT**, **SO_BINDTOIFINDEX**, **SO_TXREHASH**.
+ * 	* **IPPROTO_TCP**, which supports the following *optname*\ s:
+ * 	  **TCP_CONGESTION**, **TCP_BPF_IW**,
+ * 	  **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
+ * 	  **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
+ * 	  **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**,
+ * 	  **TCP_NODELAY**, **TCP_MAXSEG**, **TCP_WINDOW_CLAMP**,
+ * 	  **TCP_THIN_LINEAR_TIMEOUTS**, **TCP_BPF_DELACK_MAX**,
+ * 	  **TCP_BPF_RTO_MIN**.
+ * 	* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
+ * 	* **IPPROTO_IPV6**, which supports the following *optname*\ s:
+ * 	  **IPV6_TCLASS**, **IPV6_AUTOFLOWLABEL**.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_setsockopt)(void *bpf_socket, int level, int optname, void *optval, int optlen) = (void *) 49;
+
+/*
+ * bpf_skb_adjust_room
+ *
+ * 	Grow or shrink the room for data in the packet associated to
+ * 	*skb* by *len_diff*, and according to the selected *mode*.
+ *
+ * 	By default, the helper will reset any offloaded checksum
+ * 	indicator of the skb to CHECKSUM_NONE. This can be avoided
+ * 	by the following flag:
+ *
+ * 	* **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded
+ * 	  checksum data of the skb to CHECKSUM_NONE.
+ *
+ * 	There are two supported modes at this time:
+ *
+ * 	* **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
+ * 	  (room space is added or removed between the layer 2 and
+ * 	  layer 3 headers).
+ *
+ * 	* **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
+ * 	  (room space is added or removed between the layer 3 and
+ * 	  layer 4 headers).
+ *
+ * 	The following flags are supported at this time:
+ *
+ * 	* **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
+ * 	  Adjusting mss in this way is not allowed for datagrams.
+ *
+ * 	* **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
+ * 	  **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
+ * 	  Any new space is reserved to hold a tunnel header.
+ * 	  Configure skb offsets and other fields accordingly.
+ *
+ * 	* **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
+ * 	  **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
+ * 	  Use with ENCAP_L3 flags to further specify the tunnel type.
+ *
+ * 	* **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
+ * 	  Use with ENCAP_L3/L4 flags to further specify the tunnel
+ * 	  type; *len* is the length of the inner MAC header.
+ *
+ * 	* **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
+ * 	  Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
+ * 	  L2 type as Ethernet.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_adjust_room)(struct __sk_buff *skb, __s32 len_diff, __u32 mode, __u64 flags) = (void *) 50;
+
+/*
+ * bpf_redirect_map
+ *
+ * 	Redirect the packet to the endpoint referenced by *map* at
+ * 	index *key*. Depending on its type, this *map* can contain
+ * 	references to net devices (for forwarding packets through other
+ * 	ports), or to CPUs (for redirecting XDP frames to another CPU;
+ * 	but this is only implemented for native XDP (with driver
+ * 	support) as of this writing).
+ *
+ * 	The lower two bits of *flags* are used as the return code if
+ * 	the map lookup fails. This is so that the return value can be
+ * 	one of the XDP program return codes up to **XDP_TX**, as chosen
+ * 	by the caller. The higher bits of *flags* can be set to
+ * 	BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
+ *
+ * 	With BPF_F_BROADCAST the packet will be broadcasted to all the
+ * 	interfaces in the map, with BPF_F_EXCLUDE_INGRESS the ingress
+ * 	interface will be excluded when do broadcasting.
+ *
+ * 	See also **bpf_redirect**\ (), which only supports redirecting
+ * 	to an ifindex, but doesn't require a map to do so.
+ *
+ * Returns
+ * 	**XDP_REDIRECT** on success, or the value of the two lower bits
+ * 	of the *flags* argument on error.
+ */
+static long (*bpf_redirect_map)(void *map, __u64 key, __u64 flags) = (void *) 51;
+
+/*
+ * bpf_sk_redirect_map
+ *
+ * 	Redirect the packet to the socket referenced by *map* (of type
+ * 	**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
+ * 	egress interfaces can be used for redirection. The
+ * 	**BPF_F_INGRESS** value in *flags* is used to make the
+ * 	distinction (ingress path is selected if the flag is present,
+ * 	egress path otherwise). This is the only flag supported for now.
+ *
+ * Returns
+ * 	**SK_PASS** on success, or **SK_DROP** on error.
+ */
+static long (*bpf_sk_redirect_map)(struct __sk_buff *skb, void *map, __u32 key, __u64 flags) = (void *) 52;
+
+/*
+ * bpf_sock_map_update
+ *
+ * 	Add an entry to, or update a *map* referencing sockets. The
+ * 	*skops* is used as a new value for the entry associated to
+ * 	*key*. *flags* is one of:
+ *
+ * 	**BPF_NOEXIST**
+ * 		The entry for *key* must not exist in the map.
+ * 	**BPF_EXIST**
+ * 		The entry for *key* must already exist in the map.
+ * 	**BPF_ANY**
+ * 		No condition on the existence of the entry for *key*.
+ *
+ * 	If the *map* has eBPF programs (parser and verdict), those will
+ * 	be inherited by the socket being added. If the socket is
+ * 	already attached to eBPF programs, this results in an error.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_sock_map_update)(struct bpf_sock_ops *skops, void *map, void *key, __u64 flags) = (void *) 53;
+
+/*
+ * bpf_xdp_adjust_meta
+ *
+ * 	Adjust the address pointed by *xdp_md*\ **->data_meta** by
+ * 	*delta* (which can be positive or negative). Note that this
+ * 	operation modifies the address stored in *xdp_md*\ **->data**,
+ * 	so the latter must be loaded only after the helper has been
+ * 	called.
+ *
+ * 	The use of *xdp_md*\ **->data_meta** is optional and programs
+ * 	are not required to use it. The rationale is that when the
+ * 	packet is processed with XDP (e.g. as DoS filter), it is
+ * 	possible to push further meta data along with it before passing
+ * 	to the stack, and to give the guarantee that an ingress eBPF
+ * 	program attached as a TC classifier on the same device can pick
+ * 	this up for further post-processing. Since TC works with socket
+ * 	buffers, it remains possible to set from XDP the **mark** or
+ * 	**priority** pointers, or other pointers for the socket buffer.
+ * 	Having this scratch space generic and programmable allows for
+ * 	more flexibility as the user is free to store whatever meta
+ * 	data they need.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_xdp_adjust_meta)(struct xdp_md *xdp_md, int delta) = (void *) 54;
+
+/*
+ * bpf_perf_event_read_value
+ *
+ * 	Read the value of a perf event counter, and store it into *buf*
+ * 	of size *buf_size*. This helper relies on a *map* of type
+ * 	**BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
+ * 	counter is selected when *map* is updated with perf event file
+ * 	descriptors. The *map* is an array whose size is the number of
+ * 	available CPUs, and each cell contains a value relative to one
+ * 	CPU. The value to retrieve is indicated by *flags*, that
+ * 	contains the index of the CPU to look up, masked with
+ * 	**BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
+ * 	**BPF_F_CURRENT_CPU** to indicate that the value for the
+ * 	current CPU should be retrieved.
+ *
+ * 	This helper behaves in a way close to
+ * 	**bpf_perf_event_read**\ () helper, save that instead of
+ * 	just returning the value observed, it fills the *buf*
+ * 	structure. This allows for additional data to be retrieved: in
+ * 	particular, the enabled and running times (in *buf*\
+ * 	**->enabled** and *buf*\ **->running**, respectively) are
+ * 	copied. In general, **bpf_perf_event_read_value**\ () is
+ * 	recommended over **bpf_perf_event_read**\ (), which has some
+ * 	ABI issues and provides fewer functionalities.
+ *
+ * 	These values are interesting, because hardware PMU (Performance
+ * 	Monitoring Unit) counters are limited resources. When there are
+ * 	more PMU based perf events opened than available counters,
+ * 	kernel will multiplex these events so each event gets certain
+ * 	percentage (but not all) of the PMU time. In case that
+ * 	multiplexing happens, the number of samples or counter value
+ * 	will not reflect the case compared to when no multiplexing
+ * 	occurs. This makes comparison between different runs difficult.
+ * 	Typically, the counter value should be normalized before
+ * 	comparing to other experiments. The usual normalization is done
+ * 	as follows.
+ *
+ * 	::
+ *
+ * 		normalized_counter = counter * t_enabled / t_running
+ *
+ * 	Where t_enabled is the time enabled for event and t_running is
+ * 	the time running for event since last normalization. The
+ * 	enabled and running times are accumulated since the perf event
+ * 	open. To achieve scaling factor between two invocations of an
+ * 	eBPF program, users can use CPU id as the key (which is
+ * 	typical for perf array usage model) to remember the previous
+ * 	value and do the calculation inside the eBPF program.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_perf_event_read_value)(void *map, __u64 flags, struct bpf_perf_event_value *buf, __u32 buf_size) = (void *) 55;
+
+/*
+ * bpf_perf_prog_read_value
+ *
+ * 	For en eBPF program attached to a perf event, retrieve the
+ * 	value of the event counter associated to *ctx* and store it in
+ * 	the structure pointed by *buf* and of size *buf_size*. Enabled
+ * 	and running times are also stored in the structure (see
+ * 	description of helper **bpf_perf_event_read_value**\ () for
+ * 	more details).
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_perf_prog_read_value)(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, __u32 buf_size) = (void *) 56;
+
+/*
+ * bpf_getsockopt
+ *
+ * 	Emulate a call to **getsockopt()** on the socket associated to
+ * 	*bpf_socket*, which must be a full socket. The *level* at
+ * 	which the option resides and the name *optname* of the option
+ * 	must be specified, see **getsockopt(2)** for more information.
+ * 	The retrieved value is stored in the structure pointed by
+ * 	*opval* and of length *optlen*.
+ *
+ * 	*bpf_socket* should be one of the following:
+ *
+ * 	* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
+ * 	* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
+ * 	  and **BPF_CGROUP_INET6_CONNECT**.
+ *
+ * 	This helper actually implements a subset of **getsockopt()**.
+ * 	It supports the same set of *optname*\ s that is supported by
+ * 	the **bpf_setsockopt**\ () helper.  The exceptions are
+ * 	**TCP_BPF_*** is **bpf_setsockopt**\ () only and
+ * 	**TCP_SAVED_SYN** is **bpf_getsockopt**\ () only.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_getsockopt)(void *bpf_socket, int level, int optname, void *optval, int optlen) = (void *) 57;
+
+/*
+ * bpf_override_return
+ *
+ * 	Used for error injection, this helper uses kprobes to override
+ * 	the return value of the probed function, and to set it to *rc*.
+ * 	The first argument is the context *regs* on which the kprobe
+ * 	works.
+ *
+ * 	This helper works by setting the PC (program counter)
+ * 	to an override function which is run in place of the original
+ * 	probed function. This means the probed function is not run at
+ * 	all. The replacement function just returns with the required
+ * 	value.
+ *
+ * 	This helper has security implications, and thus is subject to
+ * 	restrictions. It is only available if the kernel was compiled
+ * 	with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
+ * 	option, and in this case it only works on functions tagged with
+ * 	**ALLOW_ERROR_INJECTION** in the kernel code.
+ *
+ * 	Also, the helper is only available for the architectures having
+ * 	the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
+ * 	x86 architecture is the only one to support this feature.
+ *
+ * Returns
+ * 	0
+ */
+static long (*bpf_override_return)(struct pt_regs *regs, __u64 rc) = (void *) 58;
+
+/*
+ * bpf_sock_ops_cb_flags_set
+ *
+ * 	Attempt to set the value of the **bpf_sock_ops_cb_flags** field
+ * 	for the full TCP socket associated to *bpf_sock_ops* to
+ * 	*argval*.
+ *
+ * 	The primary use of this field is to determine if there should
+ * 	be calls to eBPF programs of type
+ * 	**BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
+ * 	code. A program of the same type can change its value, per
+ * 	connection and as necessary, when the connection is
+ * 	established. This field is directly accessible for reading, but
+ * 	this helper must be used for updates in order to return an
+ * 	error if an eBPF program tries to set a callback that is not
+ * 	supported in the current kernel.
+ *
+ * 	*argval* is a flag array which can combine these flags:
+ *
+ * 	* **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
+ * 	* **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
+ * 	* **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
+ * 	* **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
+ *
+ * 	Therefore, this function can be used to clear a callback flag by
+ * 	setting the appropriate bit to zero. e.g. to disable the RTO
+ * 	callback:
+ *
+ * 	**bpf_sock_ops_cb_flags_set(bpf_sock,**
+ * 		**bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
+ *
+ * 	Here are some examples of where one could call such eBPF
+ * 	program:
+ *
+ * 	* When RTO fires.
+ * 	* When a packet is retransmitted.
+ * 	* When the connection terminates.
+ * 	* When a packet is sent.
+ * 	* When a packet is received.
+ *
+ * Returns
+ * 	Code **-EINVAL** if the socket is not a full TCP socket;
+ * 	otherwise, a positive number containing the bits that could not
+ * 	be set is returned (which comes down to 0 if all bits were set
+ * 	as required).
+ */
+static long (*bpf_sock_ops_cb_flags_set)(struct bpf_sock_ops *bpf_sock, int argval) = (void *) 59;
+
+/*
+ * bpf_msg_redirect_map
+ *
+ * 	This helper is used in programs implementing policies at the
+ * 	socket level. If the message *msg* is allowed to pass (i.e. if
+ * 	the verdict eBPF program returns **SK_PASS**), redirect it to
+ * 	the socket referenced by *map* (of type
+ * 	**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
+ * 	egress interfaces can be used for redirection. The
+ * 	**BPF_F_INGRESS** value in *flags* is used to make the
+ * 	distinction (ingress path is selected if the flag is present,
+ * 	egress path otherwise). This is the only flag supported for now.
+ *
+ * Returns
+ * 	**SK_PASS** on success, or **SK_DROP** on error.
+ */
+static long (*bpf_msg_redirect_map)(struct sk_msg_md *msg, void *map, __u32 key, __u64 flags) = (void *) 60;
+
+/*
+ * bpf_msg_apply_bytes
+ *
+ * 	For socket policies, apply the verdict of the eBPF program to
+ * 	the next *bytes* (number of bytes) of message *msg*.
+ *
+ * 	For example, this helper can be used in the following cases:
+ *
+ * 	* A single **sendmsg**\ () or **sendfile**\ () system call
+ * 	  contains multiple logical messages that the eBPF program is
+ * 	  supposed to read and for which it should apply a verdict.
+ * 	* An eBPF program only cares to read the first *bytes* of a
+ * 	  *msg*. If the message has a large payload, then setting up
+ * 	  and calling the eBPF program repeatedly for all bytes, even
+ * 	  though the verdict is already known, would create unnecessary
+ * 	  overhead.
+ *
+ * 	When called from within an eBPF program, the helper sets a
+ * 	counter internal to the BPF infrastructure, that is used to
+ * 	apply the last verdict to the next *bytes*. If *bytes* is
+ * 	smaller than the current data being processed from a
+ * 	**sendmsg**\ () or **sendfile**\ () system call, the first
+ * 	*bytes* will be sent and the eBPF program will be re-run with
+ * 	the pointer for start of data pointing to byte number *bytes*
+ * 	**+ 1**. If *bytes* is larger than the current data being
+ * 	processed, then the eBPF verdict will be applied to multiple
+ * 	**sendmsg**\ () or **sendfile**\ () calls until *bytes* are
+ * 	consumed.
+ *
+ * 	Note that if a socket closes with the internal counter holding
+ * 	a non-zero value, this is not a problem because data is not
+ * 	being buffered for *bytes* and is sent as it is received.
+ *
+ * Returns
+ * 	0
+ */
+static long (*bpf_msg_apply_bytes)(struct sk_msg_md *msg, __u32 bytes) = (void *) 61;
+
+/*
+ * bpf_msg_cork_bytes
+ *
+ * 	For socket policies, prevent the execution of the verdict eBPF
+ * 	program for message *msg* until *bytes* (byte number) have been
+ * 	accumulated.
+ *
+ * 	This can be used when one needs a specific number of bytes
+ * 	before a verdict can be assigned, even if the data spans
+ * 	multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
+ * 	case would be a user calling **sendmsg**\ () repeatedly with
+ * 	1-byte long message segments. Obviously, this is bad for
+ * 	performance, but it is still valid. If the eBPF program needs
+ * 	*bytes* bytes to validate a header, this helper can be used to
+ * 	prevent the eBPF program to be called again until *bytes* have
+ * 	been accumulated.
+ *
+ * Returns
+ * 	0
+ */
+static long (*bpf_msg_cork_bytes)(struct sk_msg_md *msg, __u32 bytes) = (void *) 62;
+
+/*
+ * bpf_msg_pull_data
+ *
+ * 	For socket policies, pull in non-linear data from user space
+ * 	for *msg* and set pointers *msg*\ **->data** and *msg*\
+ * 	**->data_end** to *start* and *end* bytes offsets into *msg*,
+ * 	respectively.
+ *
+ * 	If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
+ * 	*msg* it can only parse data that the (**data**, **data_end**)
+ * 	pointers have already consumed. For **sendmsg**\ () hooks this
+ * 	is likely the first scatterlist element. But for calls relying
+ * 	on the **sendpage** handler (e.g. **sendfile**\ ()) this will
+ * 	be the range (**0**, **0**) because the data is shared with
+ * 	user space and by default the objective is to avoid allowing
+ * 	user space to modify data while (or after) eBPF verdict is
+ * 	being decided. This helper can be used to pull in data and to
+ * 	set the start and end pointer to given values. Data will be
+ * 	copied if necessary (i.e. if data was not linear and if start
+ * 	and end pointers do not point to the same chunk).
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * 	All values for *flags* are reserved for future usage, and must
+ * 	be left at zero.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_msg_pull_data)(struct sk_msg_md *msg, __u32 start, __u32 end, __u64 flags) = (void *) 63;
+
+/*
+ * bpf_bind
+ *
+ * 	Bind the socket associated to *ctx* to the address pointed by
+ * 	*addr*, of length *addr_len*. This allows for making outgoing
+ * 	connection from the desired IP address, which can be useful for
+ * 	example when all processes inside a cgroup should use one
+ * 	single IP address on a host that has multiple IP configured.
+ *
+ * 	This helper works for IPv4 and IPv6, TCP and UDP sockets. The
+ * 	domain (*addr*\ **->sa_family**) must be **AF_INET** (or
+ * 	**AF_INET6**). It's advised to pass zero port (**sin_port**
+ * 	or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like
+ * 	behavior and lets the kernel efficiently pick up an unused
+ * 	port as long as 4-tuple is unique. Passing non-zero port might
+ * 	lead to degraded performance.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_bind)(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len) = (void *) 64;
+
+/*
+ * bpf_xdp_adjust_tail
+ *
+ * 	Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
+ * 	possible to both shrink and grow the packet tail.
+ * 	Shrink done via *delta* being a negative integer.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_xdp_adjust_tail)(struct xdp_md *xdp_md, int delta) = (void *) 65;
+
+/*
+ * bpf_skb_get_xfrm_state
+ *
+ * 	Retrieve the XFRM state (IP transform framework, see also
+ * 	**ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
+ *
+ * 	The retrieved value is stored in the **struct bpf_xfrm_state**
+ * 	pointed by *xfrm_state* and of length *size*.
+ *
+ * 	All values for *flags* are reserved for future usage, and must
+ * 	be left at zero.
+ *
+ * 	This helper is available only if the kernel was compiled with
+ * 	**CONFIG_XFRM** configuration option.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_get_xfrm_state)(struct __sk_buff *skb, __u32 index, struct bpf_xfrm_state *xfrm_state, __u32 size, __u64 flags) = (void *) 66;
+
+/*
+ * bpf_get_stack
+ *
+ * 	Return a user or a kernel stack in bpf program provided buffer.
+ * 	To achieve this, the helper needs *ctx*, which is a pointer
+ * 	to the context on which the tracing program is executed.
+ * 	To store the stacktrace, the bpf program provides *buf* with
+ * 	a nonnegative *size*.
+ *
+ * 	The last argument, *flags*, holds the number of stack frames to
+ * 	skip (from 0 to 255), masked with
+ * 	**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
+ * 	the following flags:
+ *
+ * 	**BPF_F_USER_STACK**
+ * 		Collect a user space stack instead of a kernel stack.
+ * 	**BPF_F_USER_BUILD_ID**
+ * 		Collect (build_id, file_offset) instead of ips for user
+ * 		stack, only valid if **BPF_F_USER_STACK** is also
+ * 		specified.
+ *
+ * 		*file_offset* is an offset relative to the beginning
+ * 		of the executable or shared object file backing the vma
+ * 		which the *ip* falls in. It is *not* an offset relative
+ * 		to that object's base address. Accordingly, it must be
+ * 		adjusted by adding (sh_addr - sh_offset), where
+ * 		sh_{addr,offset} correspond to the executable section
+ * 		containing *file_offset* in the object, for comparisons
+ * 		to symbols' st_value to be valid.
+ *
+ * 	**bpf_get_stack**\ () can collect up to
+ * 	**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
+ * 	to sufficient large buffer size. Note that
+ * 	this limit can be controlled with the **sysctl** program, and
+ * 	that it should be manually increased in order to profile long
+ * 	user stacks (such as stacks for Java programs). To do so, use:
+ *
+ * 	::
+ *
+ * 		# sysctl kernel.perf_event_max_stack=<new value>
+ *
+ * Returns
+ * 	The non-negative copied *buf* length equal to or less than
+ * 	*size* on success, or a negative error in case of failure.
+ */
+static long (*bpf_get_stack)(void *ctx, void *buf, __u32 size, __u64 flags) = (void *) 67;
+
+/*
+ * bpf_skb_load_bytes_relative
+ *
+ * 	This helper is similar to **bpf_skb_load_bytes**\ () in that
+ * 	it provides an easy way to load *len* bytes from *offset*
+ * 	from the packet associated to *skb*, into the buffer pointed
+ * 	by *to*. The difference to **bpf_skb_load_bytes**\ () is that
+ * 	a fifth argument *start_header* exists in order to select a
+ * 	base offset to start from. *start_header* can be one of:
+ *
+ * 	**BPF_HDR_START_MAC**
+ * 		Base offset to load data from is *skb*'s mac header.
+ * 	**BPF_HDR_START_NET**
+ * 		Base offset to load data from is *skb*'s network header.
+ *
+ * 	In general, "direct packet access" is the preferred method to
+ * 	access packet data, however, this helper is in particular useful
+ * 	in socket filters where *skb*\ **->data** does not always point
+ * 	to the start of the mac header and where "direct packet access"
+ * 	is not available.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_load_bytes_relative)(const void *skb, __u32 offset, void *to, __u32 len, __u32 start_header) = (void *) 68;
+
+/*
+ * bpf_fib_lookup
+ *
+ * 	Do FIB lookup in kernel tables using parameters in *params*.
+ * 	If lookup is successful and result shows packet is to be
+ * 	forwarded, the neighbor tables are searched for the nexthop.
+ * 	If successful (ie., FIB lookup shows forwarding and nexthop
+ * 	is resolved), the nexthop address is returned in ipv4_dst
+ * 	or ipv6_dst based on family, smac is set to mac address of
+ * 	egress device, dmac is set to nexthop mac address, rt_metric
+ * 	is set to metric from route (IPv4/IPv6 only), and ifindex
+ * 	is set to the device index of the nexthop from the FIB lookup.
+ *
+ * 	*plen* argument is the size of the passed in struct.
+ * 	*flags* argument can be a combination of one or more of the
+ * 	following values:
+ *
+ * 	**BPF_FIB_LOOKUP_DIRECT**
+ * 		Do a direct table lookup vs full lookup using FIB
+ * 		rules.
+ * 	**BPF_FIB_LOOKUP_OUTPUT**
+ * 		Perform lookup from an egress perspective (default is
+ * 		ingress).
+ *
+ * 	*ctx* is either **struct xdp_md** for XDP programs or
+ * 	**struct sk_buff** tc cls_act programs.
+ *
+ * Returns
+ * 	* < 0 if any input argument is invalid
+ * 	*   0 on success (packet is forwarded, nexthop neighbor exists)
+ * 	* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
+ * 	  packet is not forwarded or needs assist from full stack
+ *
+ * 	If lookup fails with BPF_FIB_LKUP_RET_FRAG_NEEDED, then the MTU
+ * 	was exceeded and output params->mtu_result contains the MTU.
+ */
+static long (*bpf_fib_lookup)(void *ctx, struct bpf_fib_lookup *params, int plen, __u32 flags) = (void *) 69;
+
+/*
+ * bpf_sock_hash_update
+ *
+ * 	Add an entry to, or update a sockhash *map* referencing sockets.
+ * 	The *skops* is used as a new value for the entry associated to
+ * 	*key*. *flags* is one of:
+ *
+ * 	**BPF_NOEXIST**
+ * 		The entry for *key* must not exist in the map.
+ * 	**BPF_EXIST**
+ * 		The entry for *key* must already exist in the map.
+ * 	**BPF_ANY**
+ * 		No condition on the existence of the entry for *key*.
+ *
+ * 	If the *map* has eBPF programs (parser and verdict), those will
+ * 	be inherited by the socket being added. If the socket is
+ * 	already attached to eBPF programs, this results in an error.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_sock_hash_update)(struct bpf_sock_ops *skops, void *map, void *key, __u64 flags) = (void *) 70;
+
+/*
+ * bpf_msg_redirect_hash
+ *
+ * 	This helper is used in programs implementing policies at the
+ * 	socket level. If the message *msg* is allowed to pass (i.e. if
+ * 	the verdict eBPF program returns **SK_PASS**), redirect it to
+ * 	the socket referenced by *map* (of type
+ * 	**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
+ * 	egress interfaces can be used for redirection. The
+ * 	**BPF_F_INGRESS** value in *flags* is used to make the
+ * 	distinction (ingress path is selected if the flag is present,
+ * 	egress path otherwise). This is the only flag supported for now.
+ *
+ * Returns
+ * 	**SK_PASS** on success, or **SK_DROP** on error.
+ */
+static long (*bpf_msg_redirect_hash)(struct sk_msg_md *msg, void *map, void *key, __u64 flags) = (void *) 71;
+
+/*
+ * bpf_sk_redirect_hash
+ *
+ * 	This helper is used in programs implementing policies at the
+ * 	skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
+ * 	if the verdict eBPF program returns **SK_PASS**), redirect it
+ * 	to the socket referenced by *map* (of type
+ * 	**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
+ * 	egress interfaces can be used for redirection. The
+ * 	**BPF_F_INGRESS** value in *flags* is used to make the
+ * 	distinction (ingress path is selected if the flag is present,
+ * 	egress otherwise). This is the only flag supported for now.
+ *
+ * Returns
+ * 	**SK_PASS** on success, or **SK_DROP** on error.
+ */
+static long (*bpf_sk_redirect_hash)(struct __sk_buff *skb, void *map, void *key, __u64 flags) = (void *) 72;
+
+/*
+ * bpf_lwt_push_encap
+ *
+ * 	Encapsulate the packet associated to *skb* within a Layer 3
+ * 	protocol header. This header is provided in the buffer at
+ * 	address *hdr*, with *len* its size in bytes. *type* indicates
+ * 	the protocol of the header and can be one of:
+ *
+ * 	**BPF_LWT_ENCAP_SEG6**
+ * 		IPv6 encapsulation with Segment Routing Header
+ * 		(**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
+ * 		the IPv6 header is computed by the kernel.
+ * 	**BPF_LWT_ENCAP_SEG6_INLINE**
+ * 		Only works if *skb* contains an IPv6 packet. Insert a
+ * 		Segment Routing Header (**struct ipv6_sr_hdr**) inside
+ * 		the IPv6 header.
+ * 	**BPF_LWT_ENCAP_IP**
+ * 		IP encapsulation (GRE/GUE/IPIP/etc). The outer header
+ * 		must be IPv4 or IPv6, followed by zero or more
+ * 		additional headers, up to **LWT_BPF_MAX_HEADROOM**
+ * 		total bytes in all prepended headers. Please note that
+ * 		if **skb_is_gso**\ (*skb*) is true, no more than two
+ * 		headers can be prepended, and the inner header, if
+ * 		present, should be either GRE or UDP/GUE.
+ *
+ * 	**BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
+ * 	of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
+ * 	be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
+ * 	**BPF_PROG_TYPE_LWT_XMIT**.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_lwt_push_encap)(struct __sk_buff *skb, __u32 type, void *hdr, __u32 len) = (void *) 73;
+
+/*
+ * bpf_lwt_seg6_store_bytes
+ *
+ * 	Store *len* bytes from address *from* into the packet
+ * 	associated to *skb*, at *offset*. Only the flags, tag and TLVs
+ * 	inside the outermost IPv6 Segment Routing Header can be
+ * 	modified through this helper.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_lwt_seg6_store_bytes)(struct __sk_buff *skb, __u32 offset, const void *from, __u32 len) = (void *) 74;
+
+/*
+ * bpf_lwt_seg6_adjust_srh
+ *
+ * 	Adjust the size allocated to TLVs in the outermost IPv6
+ * 	Segment Routing Header contained in the packet associated to
+ * 	*skb*, at position *offset* by *delta* bytes. Only offsets
+ * 	after the segments are accepted. *delta* can be as well
+ * 	positive (growing) as negative (shrinking).
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_lwt_seg6_adjust_srh)(struct __sk_buff *skb, __u32 offset, __s32 delta) = (void *) 75;
+
+/*
+ * bpf_lwt_seg6_action
+ *
+ * 	Apply an IPv6 Segment Routing action of type *action* to the
+ * 	packet associated to *skb*. Each action takes a parameter
+ * 	contained at address *param*, and of length *param_len* bytes.
+ * 	*action* can be one of:
+ *
+ * 	**SEG6_LOCAL_ACTION_END_X**
+ * 		End.X action: Endpoint with Layer-3 cross-connect.
+ * 		Type of *param*: **struct in6_addr**.
+ * 	**SEG6_LOCAL_ACTION_END_T**
+ * 		End.T action: Endpoint with specific IPv6 table lookup.
+ * 		Type of *param*: **int**.
+ * 	**SEG6_LOCAL_ACTION_END_B6**
+ * 		End.B6 action: Endpoint bound to an SRv6 policy.
+ * 		Type of *param*: **struct ipv6_sr_hdr**.
+ * 	**SEG6_LOCAL_ACTION_END_B6_ENCAP**
+ * 		End.B6.Encap action: Endpoint bound to an SRv6
+ * 		encapsulation policy.
+ * 		Type of *param*: **struct ipv6_sr_hdr**.
+ *
+ * 	A call to this helper is susceptible to change the underlying
+ * 	packet buffer. Therefore, at load time, all checks on pointers
+ * 	previously done by the verifier are invalidated and must be
+ * 	performed again, if the helper is used in combination with
+ * 	direct packet access.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_lwt_seg6_action)(struct __sk_buff *skb, __u32 action, void *param, __u32 param_len) = (void *) 76;
+
+/*
+ * bpf_rc_repeat
+ *
+ * 	This helper is used in programs implementing IR decoding, to
+ * 	report a successfully decoded repeat key message. This delays
+ * 	the generation of a key up event for previously generated
+ * 	key down event.
+ *
+ * 	Some IR protocols like NEC have a special IR message for
+ * 	repeating last button, for when a button is held down.
+ *
+ * 	The *ctx* should point to the lirc sample as passed into
+ * 	the program.
+ *
+ * 	This helper is only available is the kernel was compiled with
+ * 	the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ * 	"**y**".
+ *
+ * Returns
+ * 	0
+ */
+static long (*bpf_rc_repeat)(void *ctx) = (void *) 77;
+
+/*
+ * bpf_rc_keydown
+ *
+ * 	This helper is used in programs implementing IR decoding, to
+ * 	report a successfully decoded key press with *scancode*,
+ * 	*toggle* value in the given *protocol*. The scancode will be
+ * 	translated to a keycode using the rc keymap, and reported as
+ * 	an input key down event. After a period a key up event is
+ * 	generated. This period can be extended by calling either
+ * 	**bpf_rc_keydown**\ () again with the same values, or calling
+ * 	**bpf_rc_repeat**\ ().
+ *
+ * 	Some protocols include a toggle bit, in case the button was
+ * 	released and pressed again between consecutive scancodes.
+ *
+ * 	The *ctx* should point to the lirc sample as passed into
+ * 	the program.
+ *
+ * 	The *protocol* is the decoded protocol number (see
+ * 	**enum rc_proto** for some predefined values).
+ *
+ * 	This helper is only available is the kernel was compiled with
+ * 	the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ * 	"**y**".
+ *
+ * Returns
+ * 	0
+ */
+static long (*bpf_rc_keydown)(void *ctx, __u32 protocol, __u64 scancode, __u32 toggle) = (void *) 78;
+
+/*
+ * bpf_skb_cgroup_id
+ *
+ * 	Return the cgroup v2 id of the socket associated with the *skb*.
+ * 	This is roughly similar to the **bpf_get_cgroup_classid**\ ()
+ * 	helper for cgroup v1 by providing a tag resp. identifier that
+ * 	can be matched on or used for map lookups e.g. to implement
+ * 	policy. The cgroup v2 id of a given path in the hierarchy is
+ * 	exposed in user space through the f_handle API in order to get
+ * 	to the same 64-bit id.
+ *
+ * 	This helper can be used on TC egress path, but not on ingress,
+ * 	and is available only if the kernel was compiled with the
+ * 	**CONFIG_SOCK_CGROUP_DATA** configuration option.
+ *
+ * Returns
+ * 	The id is returned or 0 in case the id could not be retrieved.
+ */
+static __u64 (*bpf_skb_cgroup_id)(struct __sk_buff *skb) = (void *) 79;
+
+/*
+ * bpf_get_current_cgroup_id
+ *
+ * 	Get the current cgroup id based on the cgroup within which
+ * 	the current task is running.
+ *
+ * Returns
+ * 	A 64-bit integer containing the current cgroup id based
+ * 	on the cgroup within which the current task is running.
+ */
+static __u64 (*bpf_get_current_cgroup_id)(void) = (void *) 80;
+
+/*
+ * bpf_get_local_storage
+ *
+ * 	Get the pointer to the local storage area.
+ * 	The type and the size of the local storage is defined
+ * 	by the *map* argument.
+ * 	The *flags* meaning is specific for each map type,
+ * 	and has to be 0 for cgroup local storage.
+ *
+ * 	Depending on the BPF program type, a local storage area
+ * 	can be shared between multiple instances of the BPF program,
+ * 	running simultaneously.
+ *
+ * 	A user should care about the synchronization by himself.
+ * 	For example, by using the **BPF_ATOMIC** instructions to alter
+ * 	the shared data.
+ *
+ * Returns
+ * 	A pointer to the local storage area.
+ */
+static void *(*bpf_get_local_storage)(void *map, __u64 flags) = (void *) 81;
+
+/*
+ * bpf_sk_select_reuseport
+ *
+ * 	Select a **SO_REUSEPORT** socket from a
+ * 	**BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*.
+ * 	It checks the selected socket is matching the incoming
+ * 	request in the socket buffer.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_sk_select_reuseport)(struct sk_reuseport_md *reuse, void *map, void *key, __u64 flags) = (void *) 82;
+
+/*
+ * bpf_skb_ancestor_cgroup_id
+ *
+ * 	Return id of cgroup v2 that is ancestor of cgroup associated
+ * 	with the *skb* at the *ancestor_level*.  The root cgroup is at
+ * 	*ancestor_level* zero and each step down the hierarchy
+ * 	increments the level. If *ancestor_level* == level of cgroup
+ * 	associated with *skb*, then return value will be same as that
+ * 	of **bpf_skb_cgroup_id**\ ().
+ *
+ * 	The helper is useful to implement policies based on cgroups
+ * 	that are upper in hierarchy than immediate cgroup associated
+ * 	with *skb*.
+ *
+ * 	The format of returned id and helper limitations are same as in
+ * 	**bpf_skb_cgroup_id**\ ().
+ *
+ * Returns
+ * 	The id is returned or 0 in case the id could not be retrieved.
+ */
+static __u64 (*bpf_skb_ancestor_cgroup_id)(struct __sk_buff *skb, int ancestor_level) = (void *) 83;
+
+/*
+ * bpf_sk_lookup_tcp
+ *
+ * 	Look for TCP socket matching *tuple*, optionally in a child
+ * 	network namespace *netns*. The return value must be checked,
+ * 	and if non-**NULL**, released via **bpf_sk_release**\ ().
+ *
+ * 	The *ctx* should point to the context of the program, such as
+ * 	the skb or socket (depending on the hook in use). This is used
+ * 	to determine the base network namespace for the lookup.
+ *
+ * 	*tuple_size* must be one of:
+ *
+ * 	**sizeof**\ (*tuple*\ **->ipv4**)
+ * 		Look for an IPv4 socket.
+ * 	**sizeof**\ (*tuple*\ **->ipv6**)
+ * 		Look for an IPv6 socket.
+ *
+ * 	If the *netns* is a negative signed 32-bit integer, then the
+ * 	socket lookup table in the netns associated with the *ctx*
+ * 	will be used. For the TC hooks, this is the netns of the device
+ * 	in the skb. For socket hooks, this is the netns of the socket.
+ * 	If *netns* is any other signed 32-bit value greater than or
+ * 	equal to zero then it specifies the ID of the netns relative to
+ * 	the netns associated with the *ctx*. *netns* values beyond the
+ * 	range of 32-bit integers are reserved for future use.
+ *
+ * 	All values for *flags* are reserved for future usage, and must
+ * 	be left at zero.
+ *
+ * 	This helper is available only if the kernel was compiled with
+ * 	**CONFIG_NET** configuration option.
+ *
+ * Returns
+ * 	Pointer to **struct bpf_sock**, or **NULL** in case of failure.
+ * 	For sockets with reuseport option, the **struct bpf_sock**
+ * 	result is from *reuse*\ **->socks**\ [] using the hash of the
+ * 	tuple.
+ */
+static struct bpf_sock *(*bpf_sk_lookup_tcp)(void *ctx, struct bpf_sock_tuple *tuple, __u32 tuple_size, __u64 netns, __u64 flags) = (void *) 84;
+
+/*
+ * bpf_sk_lookup_udp
+ *
+ * 	Look for UDP socket matching *tuple*, optionally in a child
+ * 	network namespace *netns*. The return value must be checked,
+ * 	and if non-**NULL**, released via **bpf_sk_release**\ ().
+ *
+ * 	The *ctx* should point to the context of the program, such as
+ * 	the skb or socket (depending on the hook in use). This is used
+ * 	to determine the base network namespace for the lookup.
+ *
+ * 	*tuple_size* must be one of:
+ *
+ * 	**sizeof**\ (*tuple*\ **->ipv4**)
+ * 		Look for an IPv4 socket.
+ * 	**sizeof**\ (*tuple*\ **->ipv6**)
+ * 		Look for an IPv6 socket.
+ *
+ * 	If the *netns* is a negative signed 32-bit integer, then the
+ * 	socket lookup table in the netns associated with the *ctx*
+ * 	will be used. For the TC hooks, this is the netns of the device
+ * 	in the skb. For socket hooks, this is the netns of the socket.
+ * 	If *netns* is any other signed 32-bit value greater than or
+ * 	equal to zero then it specifies the ID of the netns relative to
+ * 	the netns associated with the *ctx*. *netns* values beyond the
+ * 	range of 32-bit integers are reserved for future use.
+ *
+ * 	All values for *flags* are reserved for future usage, and must
+ * 	be left at zero.
+ *
+ * 	This helper is available only if the kernel was compiled with
+ * 	**CONFIG_NET** configuration option.
+ *
+ * Returns
+ * 	Pointer to **struct bpf_sock**, or **NULL** in case of failure.
+ * 	For sockets with reuseport option, the **struct bpf_sock**
+ * 	result is from *reuse*\ **->socks**\ [] using the hash of the
+ * 	tuple.
+ */
+static struct bpf_sock *(*bpf_sk_lookup_udp)(void *ctx, struct bpf_sock_tuple *tuple, __u32 tuple_size, __u64 netns, __u64 flags) = (void *) 85;
+
+/*
+ * bpf_sk_release
+ *
+ * 	Release the reference held by *sock*. *sock* must be a
+ * 	non-**NULL** pointer that was returned from
+ * 	**bpf_sk_lookup_xxx**\ ().
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_sk_release)(void *sock) = (void *) 86;
+
+/*
+ * bpf_map_push_elem
+ *
+ * 	Push an element *value* in *map*. *flags* is one of:
+ *
+ * 	**BPF_EXIST**
+ * 		If the queue/stack is full, the oldest element is
+ * 		removed to make room for this.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_map_push_elem)(void *map, const void *value, __u64 flags) = (void *) 87;
+
+/*
+ * bpf_map_pop_elem
+ *
+ * 	Pop an element from *map*.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_map_pop_elem)(void *map, void *value) = (void *) 88;
+
+/*
+ * bpf_map_peek_elem
+ *
+ * 	Get an element from *map* without removing it.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_map_peek_elem)(void *map, void *value) = (void *) 89;
+
+/*
+ * bpf_msg_push_data
+ *
+ * 	For socket policies, insert *len* bytes into *msg* at offset
+ * 	*start*.
+ *
+ * 	If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
+ * 	*msg* it may want to insert metadata or options into the *msg*.
+ * 	This can later be read and used by any of the lower layer BPF
+ * 	hooks.
+ *
+ * 	This helper may fail if under memory pressure (a malloc
+ * 	fails) in these cases BPF programs will get an appropriate
+ * 	error and BPF programs will need to handle them.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_msg_push_data)(struct sk_msg_md *msg, __u32 start, __u32 len, __u64 flags) = (void *) 90;
+
+/*
+ * bpf_msg_pop_data
+ *
+ * 	Will remove *len* bytes from a *msg* starting at byte *start*.
+ * 	This may result in **ENOMEM** errors under certain situations if
+ * 	an allocation and copy are required due to a full ring buffer.
+ * 	However, the helper will try to avoid doing the allocation
+ * 	if possible. Other errors can occur if input parameters are
+ * 	invalid either due to *start* byte not being valid part of *msg*
+ * 	payload and/or *pop* value being to large.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_msg_pop_data)(struct sk_msg_md *msg, __u32 start, __u32 len, __u64 flags) = (void *) 91;
+
+/*
+ * bpf_rc_pointer_rel
+ *
+ * 	This helper is used in programs implementing IR decoding, to
+ * 	report a successfully decoded pointer movement.
+ *
+ * 	The *ctx* should point to the lirc sample as passed into
+ * 	the program.
+ *
+ * 	This helper is only available is the kernel was compiled with
+ * 	the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ * 	"**y**".
+ *
+ * Returns
+ * 	0
+ */
+static long (*bpf_rc_pointer_rel)(void *ctx, __s32 rel_x, __s32 rel_y) = (void *) 92;
+
+/*
+ * bpf_spin_lock
+ *
+ * 	Acquire a spinlock represented by the pointer *lock*, which is
+ * 	stored as part of a value of a map. Taking the lock allows to
+ * 	safely update the rest of the fields in that value. The
+ * 	spinlock can (and must) later be released with a call to
+ * 	**bpf_spin_unlock**\ (\ *lock*\ ).
+ *
+ * 	Spinlocks in BPF programs come with a number of restrictions
+ * 	and constraints:
+ *
+ * 	* **bpf_spin_lock** objects are only allowed inside maps of
+ * 	  types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
+ * 	  list could be extended in the future).
+ * 	* BTF description of the map is mandatory.
+ * 	* The BPF program can take ONE lock at a time, since taking two
+ * 	  or more could cause dead locks.
+ * 	* Only one **struct bpf_spin_lock** is allowed per map element.
+ * 	* When the lock is taken, calls (either BPF to BPF or helpers)
+ * 	  are not allowed.
+ * 	* The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
+ * 	  allowed inside a spinlock-ed region.
+ * 	* The BPF program MUST call **bpf_spin_unlock**\ () to release
+ * 	  the lock, on all execution paths, before it returns.
+ * 	* The BPF program can access **struct bpf_spin_lock** only via
+ * 	  the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
+ * 	  helpers. Loading or storing data into the **struct
+ * 	  bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
+ * 	* To use the **bpf_spin_lock**\ () helper, the BTF description
+ * 	  of the map value must be a struct and have **struct
+ * 	  bpf_spin_lock** *anyname*\ **;** field at the top level.
+ * 	  Nested lock inside another struct is not allowed.
+ * 	* The **struct bpf_spin_lock** *lock* field in a map value must
+ * 	  be aligned on a multiple of 4 bytes in that value.
+ * 	* Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
+ * 	  the **bpf_spin_lock** field to user space.
+ * 	* Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
+ * 	  a BPF program, do not update the **bpf_spin_lock** field.
+ * 	* **bpf_spin_lock** cannot be on the stack or inside a
+ * 	  networking packet (it can only be inside of a map values).
+ * 	* **bpf_spin_lock** is available to root only.
+ * 	* Tracing programs and socket filter programs cannot use
+ * 	  **bpf_spin_lock**\ () due to insufficient preemption checks
+ * 	  (but this may change in the future).
+ * 	* **bpf_spin_lock** is not allowed in inner maps of map-in-map.
+ *
+ * Returns
+ * 	0
+ */
+static long (*bpf_spin_lock)(struct bpf_spin_lock *lock) = (void *) 93;
+
+/*
+ * bpf_spin_unlock
+ *
+ * 	Release the *lock* previously locked by a call to
+ * 	**bpf_spin_lock**\ (\ *lock*\ ).
+ *
+ * Returns
+ * 	0
+ */
+static long (*bpf_spin_unlock)(struct bpf_spin_lock *lock) = (void *) 94;
+
+/*
+ * bpf_sk_fullsock
+ *
+ * 	This helper gets a **struct bpf_sock** pointer such
+ * 	that all the fields in this **bpf_sock** can be accessed.
+ *
+ * Returns
+ * 	A **struct bpf_sock** pointer on success, or **NULL** in
+ * 	case of failure.
+ */
+static struct bpf_sock *(*bpf_sk_fullsock)(struct bpf_sock *sk) = (void *) 95;
+
+/*
+ * bpf_tcp_sock
+ *
+ * 	This helper gets a **struct bpf_tcp_sock** pointer from a
+ * 	**struct bpf_sock** pointer.
+ *
+ * Returns
+ * 	A **struct bpf_tcp_sock** pointer on success, or **NULL** in
+ * 	case of failure.
+ */
+static struct bpf_tcp_sock *(*bpf_tcp_sock)(struct bpf_sock *sk) = (void *) 96;
+
+/*
+ * bpf_skb_ecn_set_ce
+ *
+ * 	Set ECN (Explicit Congestion Notification) field of IP header
+ * 	to **CE** (Congestion Encountered) if current value is **ECT**
+ * 	(ECN Capable Transport). Otherwise, do nothing. Works with IPv6
+ * 	and IPv4.
+ *
+ * Returns
+ * 	1 if the **CE** flag is set (either by the current helper call
+ * 	or because it was already present), 0 if it is not set.
+ */
+static long (*bpf_skb_ecn_set_ce)(struct __sk_buff *skb) = (void *) 97;
+
+/*
+ * bpf_get_listener_sock
+ *
+ * 	Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
+ * 	**bpf_sk_release**\ () is unnecessary and not allowed.
+ *
+ * Returns
+ * 	A **struct bpf_sock** pointer on success, or **NULL** in
+ * 	case of failure.
+ */
+static struct bpf_sock *(*bpf_get_listener_sock)(struct bpf_sock *sk) = (void *) 98;
+
+/*
+ * bpf_skc_lookup_tcp
+ *
+ * 	Look for TCP socket matching *tuple*, optionally in a child
+ * 	network namespace *netns*. The return value must be checked,
+ * 	and if non-**NULL**, released via **bpf_sk_release**\ ().
+ *
+ * 	This function is identical to **bpf_sk_lookup_tcp**\ (), except
+ * 	that it also returns timewait or request sockets. Use
+ * 	**bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
+ * 	full structure.
+ *
+ * 	This helper is available only if the kernel was compiled with
+ * 	**CONFIG_NET** configuration option.
+ *
+ * Returns
+ * 	Pointer to **struct bpf_sock**, or **NULL** in case of failure.
+ * 	For sockets with reuseport option, the **struct bpf_sock**
+ * 	result is from *reuse*\ **->socks**\ [] using the hash of the
+ * 	tuple.
+ */
+static struct bpf_sock *(*bpf_skc_lookup_tcp)(void *ctx, struct bpf_sock_tuple *tuple, __u32 tuple_size, __u64 netns, __u64 flags) = (void *) 99;
+
+/*
+ * bpf_tcp_check_syncookie
+ *
+ * 	Check whether *iph* and *th* contain a valid SYN cookie ACK for
+ * 	the listening socket in *sk*.
+ *
+ * 	*iph* points to the start of the IPv4 or IPv6 header, while
+ * 	*iph_len* contains **sizeof**\ (**struct iphdr**) or
+ * 	**sizeof**\ (**struct ipv6hdr**).
+ *
+ * 	*th* points to the start of the TCP header, while *th_len*
+ * 	contains the length of the TCP header (at least
+ * 	**sizeof**\ (**struct tcphdr**)).
+ *
+ * Returns
+ * 	0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
+ * 	error otherwise.
+ */
+static long (*bpf_tcp_check_syncookie)(void *sk, void *iph, __u32 iph_len, struct tcphdr *th, __u32 th_len) = (void *) 100;
+
+/*
+ * bpf_sysctl_get_name
+ *
+ * 	Get name of sysctl in /proc/sys/ and copy it into provided by
+ * 	program buffer *buf* of size *buf_len*.
+ *
+ * 	The buffer is always NUL terminated, unless it's zero-sized.
+ *
+ * 	If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
+ * 	copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
+ * 	only (e.g. "tcp_mem").
+ *
+ * Returns
+ * 	Number of character copied (not including the trailing NUL).
+ *
+ * 	**-E2BIG** if the buffer wasn't big enough (*buf* will contain
+ * 	truncated name in this case).
+ */
+static long (*bpf_sysctl_get_name)(struct bpf_sysctl *ctx, char *buf, unsigned long buf_len, __u64 flags) = (void *) 101;
+
+/*
+ * bpf_sysctl_get_current_value
+ *
+ * 	Get current value of sysctl as it is presented in /proc/sys
+ * 	(incl. newline, etc), and copy it as a string into provided
+ * 	by program buffer *buf* of size *buf_len*.
+ *
+ * 	The whole value is copied, no matter what file position user
+ * 	space issued e.g. sys_read at.
+ *
+ * 	The buffer is always NUL terminated, unless it's zero-sized.
+ *
+ * Returns
+ * 	Number of character copied (not including the trailing NUL).
+ *
+ * 	**-E2BIG** if the buffer wasn't big enough (*buf* will contain
+ * 	truncated name in this case).
+ *
+ * 	**-EINVAL** if current value was unavailable, e.g. because
+ * 	sysctl is uninitialized and read returns -EIO for it.
+ */
+static long (*bpf_sysctl_get_current_value)(struct bpf_sysctl *ctx, char *buf, unsigned long buf_len) = (void *) 102;
+
+/*
+ * bpf_sysctl_get_new_value
+ *
+ * 	Get new value being written by user space to sysctl (before
+ * 	the actual write happens) and copy it as a string into
+ * 	provided by program buffer *buf* of size *buf_len*.
+ *
+ * 	User space may write new value at file position > 0.
+ *
+ * 	The buffer is always NUL terminated, unless it's zero-sized.
+ *
+ * Returns
+ * 	Number of character copied (not including the trailing NUL).
+ *
+ * 	**-E2BIG** if the buffer wasn't big enough (*buf* will contain
+ * 	truncated name in this case).
+ *
+ * 	**-EINVAL** if sysctl is being read.
+ */
+static long (*bpf_sysctl_get_new_value)(struct bpf_sysctl *ctx, char *buf, unsigned long buf_len) = (void *) 103;
+
+/*
+ * bpf_sysctl_set_new_value
+ *
+ * 	Override new value being written by user space to sysctl with
+ * 	value provided by program in buffer *buf* of size *buf_len*.
+ *
+ * 	*buf* should contain a string in same form as provided by user
+ * 	space on sysctl write.
+ *
+ * 	User space may write new value at file position > 0. To override
+ * 	the whole sysctl value file position should be set to zero.
+ *
+ * Returns
+ * 	0 on success.
+ *
+ * 	**-E2BIG** if the *buf_len* is too big.
+ *
+ * 	**-EINVAL** if sysctl is being read.
+ */
+static long (*bpf_sysctl_set_new_value)(struct bpf_sysctl *ctx, const char *buf, unsigned long buf_len) = (void *) 104;
+
+/*
+ * bpf_strtol
+ *
+ * 	Convert the initial part of the string from buffer *buf* of
+ * 	size *buf_len* to a long integer according to the given base
+ * 	and save the result in *res*.
+ *
+ * 	The string may begin with an arbitrary amount of white space
+ * 	(as determined by **isspace**\ (3)) followed by a single
+ * 	optional '**-**' sign.
+ *
+ * 	Five least significant bits of *flags* encode base, other bits
+ * 	are currently unused.
+ *
+ * 	Base must be either 8, 10, 16 or 0 to detect it automatically
+ * 	similar to user space **strtol**\ (3).
+ *
+ * Returns
+ * 	Number of characters consumed on success. Must be positive but
+ * 	no more than *buf_len*.
+ *
+ * 	**-EINVAL** if no valid digits were found or unsupported base
+ * 	was provided.
+ *
+ * 	**-ERANGE** if resulting value was out of range.
+ */
+static long (*bpf_strtol)(const char *buf, unsigned long buf_len, __u64 flags, long *res) = (void *) 105;
+
+/*
+ * bpf_strtoul
+ *
+ * 	Convert the initial part of the string from buffer *buf* of
+ * 	size *buf_len* to an unsigned long integer according to the
+ * 	given base and save the result in *res*.
+ *
+ * 	The string may begin with an arbitrary amount of white space
+ * 	(as determined by **isspace**\ (3)).
+ *
+ * 	Five least significant bits of *flags* encode base, other bits
+ * 	are currently unused.
+ *
+ * 	Base must be either 8, 10, 16 or 0 to detect it automatically
+ * 	similar to user space **strtoul**\ (3).
+ *
+ * Returns
+ * 	Number of characters consumed on success. Must be positive but
+ * 	no more than *buf_len*.
+ *
+ * 	**-EINVAL** if no valid digits were found or unsupported base
+ * 	was provided.
+ *
+ * 	**-ERANGE** if resulting value was out of range.
+ */
+static long (*bpf_strtoul)(const char *buf, unsigned long buf_len, __u64 flags, unsigned long *res) = (void *) 106;
+
+/*
+ * bpf_sk_storage_get
+ *
+ * 	Get a bpf-local-storage from a *sk*.
+ *
+ * 	Logically, it could be thought of getting the value from
+ * 	a *map* with *sk* as the **key**.  From this
+ * 	perspective,  the usage is not much different from
+ * 	**bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
+ * 	helper enforces the key must be a full socket and the map must
+ * 	be a **BPF_MAP_TYPE_SK_STORAGE** also.
+ *
+ * 	Underneath, the value is stored locally at *sk* instead of
+ * 	the *map*.  The *map* is used as the bpf-local-storage
+ * 	"type". The bpf-local-storage "type" (i.e. the *map*) is
+ * 	searched against all bpf-local-storages residing at *sk*.
+ *
+ * 	*sk* is a kernel **struct sock** pointer for LSM program.
+ * 	*sk* is a **struct bpf_sock** pointer for other program types.
+ *
+ * 	An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
+ * 	used such that a new bpf-local-storage will be
+ * 	created if one does not exist.  *value* can be used
+ * 	together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
+ * 	the initial value of a bpf-local-storage.  If *value* is
+ * 	**NULL**, the new bpf-local-storage will be zero initialized.
+ *
+ * Returns
+ * 	A bpf-local-storage pointer is returned on success.
+ *
+ * 	**NULL** if not found or there was an error in adding
+ * 	a new bpf-local-storage.
+ */
+static void *(*bpf_sk_storage_get)(void *map, void *sk, void *value, __u64 flags) = (void *) 107;
+
+/*
+ * bpf_sk_storage_delete
+ *
+ * 	Delete a bpf-local-storage from a *sk*.
+ *
+ * Returns
+ * 	0 on success.
+ *
+ * 	**-ENOENT** if the bpf-local-storage cannot be found.
+ * 	**-EINVAL** if sk is not a fullsock (e.g. a request_sock).
+ */
+static long (*bpf_sk_storage_delete)(void *map, void *sk) = (void *) 108;
+
+/*
+ * bpf_send_signal
+ *
+ * 	Send signal *sig* to the process of the current task.
+ * 	The signal may be delivered to any of this process's threads.
+ *
+ * Returns
+ * 	0 on success or successfully queued.
+ *
+ * 	**-EBUSY** if work queue under nmi is full.
+ *
+ * 	**-EINVAL** if *sig* is invalid.
+ *
+ * 	**-EPERM** if no permission to send the *sig*.
+ *
+ * 	**-EAGAIN** if bpf program can try again.
+ */
+static long (*bpf_send_signal)(__u32 sig) = (void *) 109;
+
+/*
+ * bpf_tcp_gen_syncookie
+ *
+ * 	Try to issue a SYN cookie for the packet with corresponding
+ * 	IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
+ *
+ * 	*iph* points to the start of the IPv4 or IPv6 header, while
+ * 	*iph_len* contains **sizeof**\ (**struct iphdr**) or
+ * 	**sizeof**\ (**struct ipv6hdr**).
+ *
+ * 	*th* points to the start of the TCP header, while *th_len*
+ * 	contains the length of the TCP header with options (at least
+ * 	**sizeof**\ (**struct tcphdr**)).
+ *
+ * Returns
+ * 	On success, lower 32 bits hold the generated SYN cookie in
+ * 	followed by 16 bits which hold the MSS value for that cookie,
+ * 	and the top 16 bits are unused.
+ *
+ * 	On failure, the returned value is one of the following:
+ *
+ * 	**-EINVAL** SYN cookie cannot be issued due to error
+ *
+ * 	**-ENOENT** SYN cookie should not be issued (no SYN flood)
+ *
+ * 	**-EOPNOTSUPP** kernel configuration does not enable SYN cookies
+ *
+ * 	**-EPROTONOSUPPORT** IP packet version is not 4 or 6
+ */
+static __s64 (*bpf_tcp_gen_syncookie)(void *sk, void *iph, __u32 iph_len, struct tcphdr *th, __u32 th_len) = (void *) 110;
+
+/*
+ * bpf_skb_output
+ *
+ * 	Write raw *data* blob into a special BPF perf event held by
+ * 	*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
+ * 	event must have the following attributes: **PERF_SAMPLE_RAW**
+ * 	as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
+ * 	**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
+ *
+ * 	The *flags* are used to indicate the index in *map* for which
+ * 	the value must be put, masked with **BPF_F_INDEX_MASK**.
+ * 	Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
+ * 	to indicate that the index of the current CPU core should be
+ * 	used.
+ *
+ * 	The value to write, of *size*, is passed through eBPF stack and
+ * 	pointed by *data*.
+ *
+ * 	*ctx* is a pointer to in-kernel struct sk_buff.
+ *
+ * 	This helper is similar to **bpf_perf_event_output**\ () but
+ * 	restricted to raw_tracepoint bpf programs.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_skb_output)(void *ctx, void *map, __u64 flags, void *data, __u64 size) = (void *) 111;
+
+/*
+ * bpf_probe_read_user
+ *
+ * 	Safely attempt to read *size* bytes from user space address
+ * 	*unsafe_ptr* and store the data in *dst*.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_probe_read_user)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 112;
+
+/*
+ * bpf_probe_read_kernel
+ *
+ * 	Safely attempt to read *size* bytes from kernel space address
+ * 	*unsafe_ptr* and store the data in *dst*.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_probe_read_kernel)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 113;
+
+/*
+ * bpf_probe_read_user_str
+ *
+ * 	Copy a NUL terminated string from an unsafe user address
+ * 	*unsafe_ptr* to *dst*. The *size* should include the
+ * 	terminating NUL byte. In case the string length is smaller than
+ * 	*size*, the target is not padded with further NUL bytes. If the
+ * 	string length is larger than *size*, just *size*-1 bytes are
+ * 	copied and the last byte is set to NUL.
+ *
+ * 	On success, returns the number of bytes that were written,
+ * 	including the terminal NUL. This makes this helper useful in
+ * 	tracing programs for reading strings, and more importantly to
+ * 	get its length at runtime. See the following snippet:
+ *
+ * 	::
+ *
+ * 		SEC("kprobe/sys_open")
+ * 		void bpf_sys_open(struct pt_regs *ctx)
+ * 		{
+ * 		        char buf[PATHLEN]; // PATHLEN is defined to 256
+ * 		        int res = bpf_probe_read_user_str(buf, sizeof(buf),
+ * 			                                  ctx->di);
+ *
+ * 			// Consume buf, for example push it to
+ * 			// userspace via bpf_perf_event_output(); we
+ * 			// can use res (the string length) as event
+ * 			// size, after checking its boundaries.
+ * 		}
+ *
+ * 	In comparison, using **bpf_probe_read_user**\ () helper here
+ * 	instead to read the string would require to estimate the length
+ * 	at compile time, and would often result in copying more memory
+ * 	than necessary.
+ *
+ * 	Another useful use case is when parsing individual process
+ * 	arguments or individual environment variables navigating
+ * 	*current*\ **->mm->arg_start** and *current*\
+ * 	**->mm->env_start**: using this helper and the return value,
+ * 	one can quickly iterate at the right offset of the memory area.
+ *
+ * Returns
+ * 	On success, the strictly positive length of the output string,
+ * 	including the trailing NUL character. On error, a negative
+ * 	value.
+ */
+static long (*bpf_probe_read_user_str)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 114;
+
+/*
+ * bpf_probe_read_kernel_str
+ *
+ * 	Copy a NUL terminated string from an unsafe kernel address *unsafe_ptr*
+ * 	to *dst*. Same semantics as with **bpf_probe_read_user_str**\ () apply.
+ *
+ * Returns
+ * 	On success, the strictly positive length of the string, including
+ * 	the trailing NUL character. On error, a negative value.
+ */
+static long (*bpf_probe_read_kernel_str)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 115;
+
+/*
+ * bpf_tcp_send_ack
+ *
+ * 	Send out a tcp-ack. *tp* is the in-kernel struct **tcp_sock**.
+ * 	*rcv_nxt* is the ack_seq to be sent out.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_tcp_send_ack)(void *tp, __u32 rcv_nxt) = (void *) 116;
+
+/*
+ * bpf_send_signal_thread
+ *
+ * 	Send signal *sig* to the thread corresponding to the current task.
+ *
+ * Returns
+ * 	0 on success or successfully queued.
+ *
+ * 	**-EBUSY** if work queue under nmi is full.
+ *
+ * 	**-EINVAL** if *sig* is invalid.
+ *
+ * 	**-EPERM** if no permission to send the *sig*.
+ *
+ * 	**-EAGAIN** if bpf program can try again.
+ */
+static long (*bpf_send_signal_thread)(__u32 sig) = (void *) 117;
+
+/*
+ * bpf_jiffies64
+ *
+ * 	Obtain the 64bit jiffies
+ *
+ * Returns
+ * 	The 64 bit jiffies
+ */
+static __u64 (*bpf_jiffies64)(void) = (void *) 118;
+
+/*
+ * bpf_read_branch_records
+ *
+ * 	For an eBPF program attached to a perf event, retrieve the
+ * 	branch records (**struct perf_branch_entry**) associated to *ctx*
+ * 	and store it in the buffer pointed by *buf* up to size
+ * 	*size* bytes.
+ *
+ * Returns
+ * 	On success, number of bytes written to *buf*. On error, a
+ * 	negative value.
+ *
+ * 	The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to
+ * 	instead return the number of bytes required to store all the
+ * 	branch entries. If this flag is set, *buf* may be NULL.
+ *
+ * 	**-EINVAL** if arguments invalid or **size** not a multiple
+ * 	of **sizeof**\ (**struct perf_branch_entry**\ ).
+ *
+ * 	**-ENOENT** if architecture does not support branch records.
+ */
+static long (*bpf_read_branch_records)(struct bpf_perf_event_data *ctx, void *buf, __u32 size, __u64 flags) = (void *) 119;
+
+/*
+ * bpf_get_ns_current_pid_tgid
+ *
+ * 	Returns 0 on success, values for *pid* and *tgid* as seen from the current
+ * 	*namespace* will be returned in *nsdata*.
+ *
+ * Returns
+ * 	0 on success, or one of the following in case of failure:
+ *
+ * 	**-EINVAL** if dev and inum supplied don't match dev_t and inode number
+ * 	with nsfs of current task, or if dev conversion to dev_t lost high bits.
+ *
+ * 	**-ENOENT** if pidns does not exists for the current task.
+ */
+static long (*bpf_get_ns_current_pid_tgid)(__u64 dev, __u64 ino, struct bpf_pidns_info *nsdata, __u32 size) = (void *) 120;
+
+/*
+ * bpf_xdp_output
+ *
+ * 	Write raw *data* blob into a special BPF perf event held by
+ * 	*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
+ * 	event must have the following attributes: **PERF_SAMPLE_RAW**
+ * 	as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
+ * 	**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
+ *
+ * 	The *flags* are used to indicate the index in *map* for which
+ * 	the value must be put, masked with **BPF_F_INDEX_MASK**.
+ * 	Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
+ * 	to indicate that the index of the current CPU core should be
+ * 	used.
+ *
+ * 	The value to write, of *size*, is passed through eBPF stack and
+ * 	pointed by *data*.
+ *
+ * 	*ctx* is a pointer to in-kernel struct xdp_buff.
+ *
+ * 	This helper is similar to **bpf_perf_eventoutput**\ () but
+ * 	restricted to raw_tracepoint bpf programs.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_xdp_output)(void *ctx, void *map, __u64 flags, void *data, __u64 size) = (void *) 121;
+
+/*
+ * bpf_get_netns_cookie
+ *
+ * 	Retrieve the cookie (generated by the kernel) of the network
+ * 	namespace the input *ctx* is associated with. The network
+ * 	namespace cookie remains stable for its lifetime and provides
+ * 	a global identifier that can be assumed unique. If *ctx* is
+ * 	NULL, then the helper returns the cookie for the initial
+ * 	network namespace. The cookie itself is very similar to that
+ * 	of **bpf_get_socket_cookie**\ () helper, but for network
+ * 	namespaces instead of sockets.
+ *
+ * Returns
+ * 	A 8-byte long opaque number.
+ */
+static __u64 (*bpf_get_netns_cookie)(void *ctx) = (void *) 122;
+
+/*
+ * bpf_get_current_ancestor_cgroup_id
+ *
+ * 	Return id of cgroup v2 that is ancestor of the cgroup associated
+ * 	with the current task at the *ancestor_level*. The root cgroup
+ * 	is at *ancestor_level* zero and each step down the hierarchy
+ * 	increments the level. If *ancestor_level* == level of cgroup
+ * 	associated with the current task, then return value will be the
+ * 	same as that of **bpf_get_current_cgroup_id**\ ().
+ *
+ * 	The helper is useful to implement policies based on cgroups
+ * 	that are upper in hierarchy than immediate cgroup associated
+ * 	with the current task.
+ *
+ * 	The format of returned id and helper limitations are same as in
+ * 	**bpf_get_current_cgroup_id**\ ().
+ *
+ * Returns
+ * 	The id is returned or 0 in case the id could not be retrieved.
+ */
+static __u64 (*bpf_get_current_ancestor_cgroup_id)(int ancestor_level) = (void *) 123;
+
+/*
+ * bpf_sk_assign
+ *
+ * 	Helper is overloaded depending on BPF program type. This
+ * 	description applies to **BPF_PROG_TYPE_SCHED_CLS** and
+ * 	**BPF_PROG_TYPE_SCHED_ACT** programs.
+ *
+ * 	Assign the *sk* to the *skb*. When combined with appropriate
+ * 	routing configuration to receive the packet towards the socket,
+ * 	will cause *skb* to be delivered to the specified socket.
+ * 	Subsequent redirection of *skb* via  **bpf_redirect**\ (),
+ * 	**bpf_clone_redirect**\ () or other methods outside of BPF may
+ * 	interfere with successful delivery to the socket.
+ *
+ * 	This operation is only valid from TC ingress path.
+ *
+ * 	The *flags* argument must be zero.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure:
+ *
+ * 	**-EINVAL** if specified *flags* are not supported.
+ *
+ * 	**-ENOENT** if the socket is unavailable for assignment.
+ *
+ * 	**-ENETUNREACH** if the socket is unreachable (wrong netns).
+ *
+ * 	**-EOPNOTSUPP** if the operation is not supported, for example
+ * 	a call from outside of TC ingress.
+ *
+ * 	**-ESOCKTNOSUPPORT** if the socket type is not supported
+ * 	(reuseport).
+ */
+static long (*bpf_sk_assign)(void *ctx, void *sk, __u64 flags) = (void *) 124;
+
+/*
+ * bpf_ktime_get_boot_ns
+ *
+ * 	Return the time elapsed since system boot, in nanoseconds.
+ * 	Does include the time the system was suspended.
+ * 	See: **clock_gettime**\ (**CLOCK_BOOTTIME**)
+ *
+ * Returns
+ * 	Current *ktime*.
+ */
+static __u64 (*bpf_ktime_get_boot_ns)(void) = (void *) 125;
+
+/*
+ * bpf_seq_printf
+ *
+ * 	**bpf_seq_printf**\ () uses seq_file **seq_printf**\ () to print
+ * 	out the format string.
+ * 	The *m* represents the seq_file. The *fmt* and *fmt_size* are for
+ * 	the format string itself. The *data* and *data_len* are format string
+ * 	arguments. The *data* are a **u64** array and corresponding format string
+ * 	values are stored in the array. For strings and pointers where pointees
+ * 	are accessed, only the pointer values are stored in the *data* array.
+ * 	The *data_len* is the size of *data* in bytes - must be a multiple of 8.
+ *
+ * 	Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory.
+ * 	Reading kernel memory may fail due to either invalid address or
+ * 	valid address but requiring a major memory fault. If reading kernel memory
+ * 	fails, the string for **%s** will be an empty string, and the ip
+ * 	address for **%p{i,I}{4,6}** will be 0. Not returning error to
+ * 	bpf program is consistent with what **bpf_trace_printk**\ () does for now.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure:
+ *
+ * 	**-EBUSY** if per-CPU memory copy buffer is busy, can try again
+ * 	by returning 1 from bpf program.
+ *
+ * 	**-EINVAL** if arguments are invalid, or if *fmt* is invalid/unsupported.
+ *
+ * 	**-E2BIG** if *fmt* contains too many format specifiers.
+ *
+ * 	**-EOVERFLOW** if an overflow happened: The same object will be tried again.
+ */
+static long (*bpf_seq_printf)(struct seq_file *m, const char *fmt, __u32 fmt_size, const void *data, __u32 data_len) = (void *) 126;
+
+/*
+ * bpf_seq_write
+ *
+ * 	**bpf_seq_write**\ () uses seq_file **seq_write**\ () to write the data.
+ * 	The *m* represents the seq_file. The *data* and *len* represent the
+ * 	data to write in bytes.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure:
+ *
+ * 	**-EOVERFLOW** if an overflow happened: The same object will be tried again.
+ */
+static long (*bpf_seq_write)(struct seq_file *m, const void *data, __u32 len) = (void *) 127;
+
+/*
+ * bpf_sk_cgroup_id
+ *
+ * 	Return the cgroup v2 id of the socket *sk*.
+ *
+ * 	*sk* must be a non-**NULL** pointer to a socket, e.g. one
+ * 	returned from **bpf_sk_lookup_xxx**\ (),
+ * 	**bpf_sk_fullsock**\ (), etc. The format of returned id is
+ * 	same as in **bpf_skb_cgroup_id**\ ().
+ *
+ * 	This helper is available only if the kernel was compiled with
+ * 	the **CONFIG_SOCK_CGROUP_DATA** configuration option.
+ *
+ * Returns
+ * 	The id is returned or 0 in case the id could not be retrieved.
+ */
+static __u64 (*bpf_sk_cgroup_id)(void *sk) = (void *) 128;
+
+/*
+ * bpf_sk_ancestor_cgroup_id
+ *
+ * 	Return id of cgroup v2 that is ancestor of cgroup associated
+ * 	with the *sk* at the *ancestor_level*.  The root cgroup is at
+ * 	*ancestor_level* zero and each step down the hierarchy
+ * 	increments the level. If *ancestor_level* == level of cgroup
+ * 	associated with *sk*, then return value will be same as that
+ * 	of **bpf_sk_cgroup_id**\ ().
+ *
+ * 	The helper is useful to implement policies based on cgroups
+ * 	that are upper in hierarchy than immediate cgroup associated
+ * 	with *sk*.
+ *
+ * 	The format of returned id and helper limitations are same as in
+ * 	**bpf_sk_cgroup_id**\ ().
+ *
+ * Returns
+ * 	The id is returned or 0 in case the id could not be retrieved.
+ */
+static __u64 (*bpf_sk_ancestor_cgroup_id)(void *sk, int ancestor_level) = (void *) 129;
+
+/*
+ * bpf_ringbuf_output
+ *
+ * 	Copy *size* bytes from *data* into a ring buffer *ringbuf*.
+ * 	If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
+ * 	of new data availability is sent.
+ * 	If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
+ * 	of new data availability is sent unconditionally.
+ * 	If **0** is specified in *flags*, an adaptive notification
+ * 	of new data availability is sent.
+ *
+ * 	An adaptive notification is a notification sent whenever the user-space
+ * 	process has caught up and consumed all available payloads. In case the user-space
+ * 	process is still processing a previous payload, then no notification is needed
+ * 	as it will process the newly added payload automatically.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_ringbuf_output)(void *ringbuf, void *data, __u64 size, __u64 flags) = (void *) 130;
+
+/*
+ * bpf_ringbuf_reserve
+ *
+ * 	Reserve *size* bytes of payload in a ring buffer *ringbuf*.
+ * 	*flags* must be 0.
+ *
+ * Returns
+ * 	Valid pointer with *size* bytes of memory available; NULL,
+ * 	otherwise.
+ */
+static void *(*bpf_ringbuf_reserve)(void *ringbuf, __u64 size, __u64 flags) = (void *) 131;
+
+/*
+ * bpf_ringbuf_submit
+ *
+ * 	Submit reserved ring buffer sample, pointed to by *data*.
+ * 	If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
+ * 	of new data availability is sent.
+ * 	If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
+ * 	of new data availability is sent unconditionally.
+ * 	If **0** is specified in *flags*, an adaptive notification
+ * 	of new data availability is sent.
+ *
+ * 	See 'bpf_ringbuf_output()' for the definition of adaptive notification.
+ *
+ * Returns
+ * 	Nothing. Always succeeds.
+ */
+static void (*bpf_ringbuf_submit)(void *data, __u64 flags) = (void *) 132;
+
+/*
+ * bpf_ringbuf_discard
+ *
+ * 	Discard reserved ring buffer sample, pointed to by *data*.
+ * 	If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
+ * 	of new data availability is sent.
+ * 	If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
+ * 	of new data availability is sent unconditionally.
+ * 	If **0** is specified in *flags*, an adaptive notification
+ * 	of new data availability is sent.
+ *
+ * 	See 'bpf_ringbuf_output()' for the definition of adaptive notification.
+ *
+ * Returns
+ * 	Nothing. Always succeeds.
+ */
+static void (*bpf_ringbuf_discard)(void *data, __u64 flags) = (void *) 133;
+
+/*
+ * bpf_ringbuf_query
+ *
+ * 	Query various characteristics of provided ring buffer. What
+ * 	exactly is queries is determined by *flags*:
+ *
+ * 	* **BPF_RB_AVAIL_DATA**: Amount of data not yet consumed.
+ * 	* **BPF_RB_RING_SIZE**: The size of ring buffer.
+ * 	* **BPF_RB_CONS_POS**: Consumer position (can wrap around).
+ * 	* **BPF_RB_PROD_POS**: Producer(s) position (can wrap around).
+ *
+ * 	Data returned is just a momentary snapshot of actual values
+ * 	and could be inaccurate, so this facility should be used to
+ * 	power heuristics and for reporting, not to make 100% correct
+ * 	calculation.
+ *
+ * Returns
+ * 	Requested value, or 0, if *flags* are not recognized.
+ */
+static __u64 (*bpf_ringbuf_query)(void *ringbuf, __u64 flags) = (void *) 134;
+
+/*
+ * bpf_csum_level
+ *
+ * 	Change the skbs checksum level by one layer up or down, or
+ * 	reset it entirely to none in order to have the stack perform
+ * 	checksum validation. The level is applicable to the following
+ * 	protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of
+ * 	| ETH | IP | UDP | GUE | IP | TCP | into | ETH | IP | TCP |
+ * 	through **bpf_skb_adjust_room**\ () helper with passing in
+ * 	**BPF_F_ADJ_ROOM_NO_CSUM_RESET** flag would require one	call
+ * 	to **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_DEC** since
+ * 	the UDP header is removed. Similarly, an encap of the latter
+ * 	into the former could be accompanied by a helper call to
+ * 	**bpf_csum_level**\ () with **BPF_CSUM_LEVEL_INC** if the
+ * 	skb is still intended to be processed in higher layers of the
+ * 	stack instead of just egressing at tc.
+ *
+ * 	There are three supported level settings at this time:
+ *
+ * 	* **BPF_CSUM_LEVEL_INC**: Increases skb->csum_level for skbs
+ * 	  with CHECKSUM_UNNECESSARY.
+ * 	* **BPF_CSUM_LEVEL_DEC**: Decreases skb->csum_level for skbs
+ * 	  with CHECKSUM_UNNECESSARY.
+ * 	* **BPF_CSUM_LEVEL_RESET**: Resets skb->csum_level to 0 and
+ * 	  sets CHECKSUM_NONE to force checksum validation by the stack.
+ * 	* **BPF_CSUM_LEVEL_QUERY**: No-op, returns the current
+ * 	  skb->csum_level.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure. In the
+ * 	case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
+ * 	is returned or the error code -EACCES in case the skb is not
+ * 	subject to CHECKSUM_UNNECESSARY.
+ */
+static long (*bpf_csum_level)(struct __sk_buff *skb, __u64 level) = (void *) 135;
+
+/*
+ * bpf_skc_to_tcp6_sock
+ *
+ * 	Dynamically cast a *sk* pointer to a *tcp6_sock* pointer.
+ *
+ * Returns
+ * 	*sk* if casting is valid, or **NULL** otherwise.
+ */
+static struct tcp6_sock *(*bpf_skc_to_tcp6_sock)(void *sk) = (void *) 136;
+
+/*
+ * bpf_skc_to_tcp_sock
+ *
+ * 	Dynamically cast a *sk* pointer to a *tcp_sock* pointer.
+ *
+ * Returns
+ * 	*sk* if casting is valid, or **NULL** otherwise.
+ */
+static struct tcp_sock *(*bpf_skc_to_tcp_sock)(void *sk) = (void *) 137;
+
+/*
+ * bpf_skc_to_tcp_timewait_sock
+ *
+ * 	Dynamically cast a *sk* pointer to a *tcp_timewait_sock* pointer.
+ *
+ * Returns
+ * 	*sk* if casting is valid, or **NULL** otherwise.
+ */
+static struct tcp_timewait_sock *(*bpf_skc_to_tcp_timewait_sock)(void *sk) = (void *) 138;
+
+/*
+ * bpf_skc_to_tcp_request_sock
+ *
+ * 	Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.
+ *
+ * Returns
+ * 	*sk* if casting is valid, or **NULL** otherwise.
+ */
+static struct tcp_request_sock *(*bpf_skc_to_tcp_request_sock)(void *sk) = (void *) 139;
+
+/*
+ * bpf_skc_to_udp6_sock
+ *
+ * 	Dynamically cast a *sk* pointer to a *udp6_sock* pointer.
+ *
+ * Returns
+ * 	*sk* if casting is valid, or **NULL** otherwise.
+ */
+static struct udp6_sock *(*bpf_skc_to_udp6_sock)(void *sk) = (void *) 140;
+
+/*
+ * bpf_get_task_stack
+ *
+ * 	Return a user or a kernel stack in bpf program provided buffer.
+ * 	To achieve this, the helper needs *task*, which is a valid
+ * 	pointer to **struct task_struct**. To store the stacktrace, the
+ * 	bpf program provides *buf* with a nonnegative *size*.
+ *
+ * 	The last argument, *flags*, holds the number of stack frames to
+ * 	skip (from 0 to 255), masked with
+ * 	**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
+ * 	the following flags:
+ *
+ * 	**BPF_F_USER_STACK**
+ * 		Collect a user space stack instead of a kernel stack.
+ * 	**BPF_F_USER_BUILD_ID**
+ * 		Collect buildid+offset instead of ips for user stack,
+ * 		only valid if **BPF_F_USER_STACK** is also specified.
+ *
+ * 	**bpf_get_task_stack**\ () can collect up to
+ * 	**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
+ * 	to sufficient large buffer size. Note that
+ * 	this limit can be controlled with the **sysctl** program, and
+ * 	that it should be manually increased in order to profile long
+ * 	user stacks (such as stacks for Java programs). To do so, use:
+ *
+ * 	::
+ *
+ * 		# sysctl kernel.perf_event_max_stack=<new value>
+ *
+ * Returns
+ * 	The non-negative copied *buf* length equal to or less than
+ * 	*size* on success, or a negative error in case of failure.
+ */
+static long (*bpf_get_task_stack)(struct task_struct *task, void *buf, __u32 size, __u64 flags) = (void *) 141;
+
+/*
+ * bpf_load_hdr_opt
+ *
+ * 	Load header option.  Support reading a particular TCP header
+ * 	option for bpf program (**BPF_PROG_TYPE_SOCK_OPS**).
+ *
+ * 	If *flags* is 0, it will search the option from the
+ * 	*skops*\ **->skb_data**.  The comment in **struct bpf_sock_ops**
+ * 	has details on what skb_data contains under different
+ * 	*skops*\ **->op**.
+ *
+ * 	The first byte of the *searchby_res* specifies the
+ * 	kind that it wants to search.
+ *
+ * 	If the searching kind is an experimental kind
+ * 	(i.e. 253 or 254 according to RFC6994).  It also
+ * 	needs to specify the "magic" which is either
+ * 	2 bytes or 4 bytes.  It then also needs to
+ * 	specify the size of the magic by using
+ * 	the 2nd byte which is "kind-length" of a TCP
+ * 	header option and the "kind-length" also
+ * 	includes the first 2 bytes "kind" and "kind-length"
+ * 	itself as a normal TCP header option also does.
+ *
+ * 	For example, to search experimental kind 254 with
+ * 	2 byte magic 0xeB9F, the searchby_res should be
+ * 	[ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ].
+ *
+ * 	To search for the standard window scale option (3),
+ * 	the *searchby_res* should be [ 3, 0, 0, .... 0 ].
+ * 	Note, kind-length must be 0 for regular option.
+ *
+ * 	Searching for No-Op (0) and End-of-Option-List (1) are
+ * 	not supported.
+ *
+ * 	*len* must be at least 2 bytes which is the minimal size
+ * 	of a header option.
+ *
+ * 	Supported flags:
+ *
+ * 	* **BPF_LOAD_HDR_OPT_TCP_SYN** to search from the
+ * 	  saved_syn packet or the just-received syn packet.
+ *
+ *
+ * Returns
+ * 	> 0 when found, the header option is copied to *searchby_res*.
+ * 	The return value is the total length copied. On failure, a
+ * 	negative error code is returned:
+ *
+ * 	**-EINVAL** if a parameter is invalid.
+ *
+ * 	**-ENOMSG** if the option is not found.
+ *
+ * 	**-ENOENT** if no syn packet is available when
+ * 	**BPF_LOAD_HDR_OPT_TCP_SYN** is used.
+ *
+ * 	**-ENOSPC** if there is not enough space.  Only *len* number of
+ * 	bytes are copied.
+ *
+ * 	**-EFAULT** on failure to parse the header options in the
+ * 	packet.
+ *
+ * 	**-EPERM** if the helper cannot be used under the current
+ * 	*skops*\ **->op**.
+ */
+static long (*bpf_load_hdr_opt)(struct bpf_sock_ops *skops, void *searchby_res, __u32 len, __u64 flags) = (void *) 142;
+
+/*
+ * bpf_store_hdr_opt
+ *
+ * 	Store header option.  The data will be copied
+ * 	from buffer *from* with length *len* to the TCP header.
+ *
+ * 	The buffer *from* should have the whole option that
+ * 	includes the kind, kind-length, and the actual
+ * 	option data.  The *len* must be at least kind-length
+ * 	long.  The kind-length does not have to be 4 byte
+ * 	aligned.  The kernel will take care of the padding
+ * 	and setting the 4 bytes aligned value to th->doff.
+ *
+ * 	This helper will check for duplicated option
+ * 	by searching the same option in the outgoing skb.
+ *
+ * 	This helper can only be called during
+ * 	**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
+ *
+ *
+ * Returns
+ * 	0 on success, or negative error in case of failure:
+ *
+ * 	**-EINVAL** If param is invalid.
+ *
+ * 	**-ENOSPC** if there is not enough space in the header.
+ * 	Nothing has been written
+ *
+ * 	**-EEXIST** if the option already exists.
+ *
+ * 	**-EFAULT** on failure to parse the existing header options.
+ *
+ * 	**-EPERM** if the helper cannot be used under the current
+ * 	*skops*\ **->op**.
+ */
+static long (*bpf_store_hdr_opt)(struct bpf_sock_ops *skops, const void *from, __u32 len, __u64 flags) = (void *) 143;
+
+/*
+ * bpf_reserve_hdr_opt
+ *
+ * 	Reserve *len* bytes for the bpf header option.  The
+ * 	space will be used by **bpf_store_hdr_opt**\ () later in
+ * 	**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
+ *
+ * 	If **bpf_reserve_hdr_opt**\ () is called multiple times,
+ * 	the total number of bytes will be reserved.
+ *
+ * 	This helper can only be called during
+ * 	**BPF_SOCK_OPS_HDR_OPT_LEN_CB**.
+ *
+ *
+ * Returns
+ * 	0 on success, or negative error in case of failure:
+ *
+ * 	**-EINVAL** if a parameter is invalid.
+ *
+ * 	**-ENOSPC** if there is not enough space in the header.
+ *
+ * 	**-EPERM** if the helper cannot be used under the current
+ * 	*skops*\ **->op**.
+ */
+static long (*bpf_reserve_hdr_opt)(struct bpf_sock_ops *skops, __u32 len, __u64 flags) = (void *) 144;
+
+/*
+ * bpf_inode_storage_get
+ *
+ * 	Get a bpf_local_storage from an *inode*.
+ *
+ * 	Logically, it could be thought of as getting the value from
+ * 	a *map* with *inode* as the **key**.  From this
+ * 	perspective,  the usage is not much different from
+ * 	**bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
+ * 	helper enforces the key must be an inode and the map must also
+ * 	be a **BPF_MAP_TYPE_INODE_STORAGE**.
+ *
+ * 	Underneath, the value is stored locally at *inode* instead of
+ * 	the *map*.  The *map* is used as the bpf-local-storage
+ * 	"type". The bpf-local-storage "type" (i.e. the *map*) is
+ * 	searched against all bpf_local_storage residing at *inode*.
+ *
+ * 	An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
+ * 	used such that a new bpf_local_storage will be
+ * 	created if one does not exist.  *value* can be used
+ * 	together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
+ * 	the initial value of a bpf_local_storage.  If *value* is
+ * 	**NULL**, the new bpf_local_storage will be zero initialized.
+ *
+ * Returns
+ * 	A bpf_local_storage pointer is returned on success.
+ *
+ * 	**NULL** if not found or there was an error in adding
+ * 	a new bpf_local_storage.
+ */
+static void *(*bpf_inode_storage_get)(void *map, void *inode, void *value, __u64 flags) = (void *) 145;
+
+/*
+ * bpf_inode_storage_delete
+ *
+ * 	Delete a bpf_local_storage from an *inode*.
+ *
+ * Returns
+ * 	0 on success.
+ *
+ * 	**-ENOENT** if the bpf_local_storage cannot be found.
+ */
+static int (*bpf_inode_storage_delete)(void *map, void *inode) = (void *) 146;
+
+/*
+ * bpf_d_path
+ *
+ * 	Return full path for given **struct path** object, which
+ * 	needs to be the kernel BTF *path* object. The path is
+ * 	returned in the provided buffer *buf* of size *sz* and
+ * 	is zero terminated.
+ *
+ *
+ * Returns
+ * 	On success, the strictly positive length of the string,
+ * 	including the trailing NUL character. On error, a negative
+ * 	value.
+ */
+static long (*bpf_d_path)(struct path *path, char *buf, __u32 sz) = (void *) 147;
+
+/*
+ * bpf_copy_from_user
+ *
+ * 	Read *size* bytes from user space address *user_ptr* and store
+ * 	the data in *dst*. This is a wrapper of **copy_from_user**\ ().
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_copy_from_user)(void *dst, __u32 size, const void *user_ptr) = (void *) 148;
+
+/*
+ * bpf_snprintf_btf
+ *
+ * 	Use BTF to store a string representation of *ptr*->ptr in *str*,
+ * 	using *ptr*->type_id.  This value should specify the type
+ * 	that *ptr*->ptr points to. LLVM __builtin_btf_type_id(type, 1)
+ * 	can be used to look up vmlinux BTF type ids. Traversing the
+ * 	data structure using BTF, the type information and values are
+ * 	stored in the first *str_size* - 1 bytes of *str*.  Safe copy of
+ * 	the pointer data is carried out to avoid kernel crashes during
+ * 	operation.  Smaller types can use string space on the stack;
+ * 	larger programs can use map data to store the string
+ * 	representation.
+ *
+ * 	The string can be subsequently shared with userspace via
+ * 	bpf_perf_event_output() or ring buffer interfaces.
+ * 	bpf_trace_printk() is to be avoided as it places too small
+ * 	a limit on string size to be useful.
+ *
+ * 	*flags* is a combination of
+ *
+ * 	**BTF_F_COMPACT**
+ * 		no formatting around type information
+ * 	**BTF_F_NONAME**
+ * 		no struct/union member names/types
+ * 	**BTF_F_PTR_RAW**
+ * 		show raw (unobfuscated) pointer values;
+ * 		equivalent to printk specifier %px.
+ * 	**BTF_F_ZERO**
+ * 		show zero-valued struct/union members; they
+ * 		are not displayed by default
+ *
+ *
+ * Returns
+ * 	The number of bytes that were written (or would have been
+ * 	written if output had to be truncated due to string size),
+ * 	or a negative error in cases of failure.
+ */
+static long (*bpf_snprintf_btf)(char *str, __u32 str_size, struct btf_ptr *ptr, __u32 btf_ptr_size, __u64 flags) = (void *) 149;
+
+/*
+ * bpf_seq_printf_btf
+ *
+ * 	Use BTF to write to seq_write a string representation of
+ * 	*ptr*->ptr, using *ptr*->type_id as per bpf_snprintf_btf().
+ * 	*flags* are identical to those used for bpf_snprintf_btf.
+ *
+ * Returns
+ * 	0 on success or a negative error in case of failure.
+ */
+static long (*bpf_seq_printf_btf)(struct seq_file *m, struct btf_ptr *ptr, __u32 ptr_size, __u64 flags) = (void *) 150;
+
+/*
+ * bpf_skb_cgroup_classid
+ *
+ * 	See **bpf_get_cgroup_classid**\ () for the main description.
+ * 	This helper differs from **bpf_get_cgroup_classid**\ () in that
+ * 	the cgroup v1 net_cls class is retrieved only from the *skb*'s
+ * 	associated socket instead of the current process.
+ *
+ * Returns
+ * 	The id is returned or 0 in case the id could not be retrieved.
+ */
+static __u64 (*bpf_skb_cgroup_classid)(struct __sk_buff *skb) = (void *) 151;
+
+/*
+ * bpf_redirect_neigh
+ *
+ * 	Redirect the packet to another net device of index *ifindex*
+ * 	and fill in L2 addresses from neighboring subsystem. This helper
+ * 	is somewhat similar to **bpf_redirect**\ (), except that it
+ * 	populates L2 addresses as well, meaning, internally, the helper
+ * 	relies on the neighbor lookup for the L2 address of the nexthop.
+ *
+ * 	The helper will perform a FIB lookup based on the skb's
+ * 	networking header to get the address of the next hop, unless
+ * 	this is supplied by the caller in the *params* argument. The
+ * 	*plen* argument indicates the len of *params* and should be set
+ * 	to 0 if *params* is NULL.
+ *
+ * 	The *flags* argument is reserved and must be 0. The helper is
+ * 	currently only supported for tc BPF program types, and enabled
+ * 	for IPv4 and IPv6 protocols.
+ *
+ * Returns
+ * 	The helper returns **TC_ACT_REDIRECT** on success or
+ * 	**TC_ACT_SHOT** on error.
+ */
+static long (*bpf_redirect_neigh)(__u32 ifindex, struct bpf_redir_neigh *params, int plen, __u64 flags) = (void *) 152;
+
+/*
+ * bpf_per_cpu_ptr
+ *
+ * 	Take a pointer to a percpu ksym, *percpu_ptr*, and return a
+ * 	pointer to the percpu kernel variable on *cpu*. A ksym is an
+ * 	extern variable decorated with '__ksym'. For ksym, there is a
+ * 	global var (either static or global) defined of the same name
+ * 	in the kernel. The ksym is percpu if the global var is percpu.
+ * 	The returned pointer points to the global percpu var on *cpu*.
+ *
+ * 	bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
+ * 	kernel, except that bpf_per_cpu_ptr() may return NULL. This
+ * 	happens if *cpu* is larger than nr_cpu_ids. The caller of
+ * 	bpf_per_cpu_ptr() must check the returned value.
+ *
+ * Returns
+ * 	A pointer pointing to the kernel percpu variable on *cpu*, or
+ * 	NULL, if *cpu* is invalid.
+ */
+static void *(*bpf_per_cpu_ptr)(const void *percpu_ptr, __u32 cpu) = (void *) 153;
+
+/*
+ * bpf_this_cpu_ptr
+ *
+ * 	Take a pointer to a percpu ksym, *percpu_ptr*, and return a
+ * 	pointer to the percpu kernel variable on this cpu. See the
+ * 	description of 'ksym' in **bpf_per_cpu_ptr**\ ().
+ *
+ * 	bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in
+ * 	the kernel. Different from **bpf_per_cpu_ptr**\ (), it would
+ * 	never return NULL.
+ *
+ * Returns
+ * 	A pointer pointing to the kernel percpu variable on this cpu.
+ */
+static void *(*bpf_this_cpu_ptr)(const void *percpu_ptr) = (void *) 154;
+
+/*
+ * bpf_redirect_peer
+ *
+ * 	Redirect the packet to another net device of index *ifindex*.
+ * 	This helper is somewhat similar to **bpf_redirect**\ (), except
+ * 	that the redirection happens to the *ifindex*' peer device and
+ * 	the netns switch takes place from ingress to ingress without
+ * 	going through the CPU's backlog queue.
+ *
+ * 	The *flags* argument is reserved and must be 0. The helper is
+ * 	currently only supported for tc BPF program types at the ingress
+ * 	hook and for veth device types. The peer device must reside in a
+ * 	different network namespace.
+ *
+ * Returns
+ * 	The helper returns **TC_ACT_REDIRECT** on success or
+ * 	**TC_ACT_SHOT** on error.
+ */
+static long (*bpf_redirect_peer)(__u32 ifindex, __u64 flags) = (void *) 155;
+
+/*
+ * bpf_task_storage_get
+ *
+ * 	Get a bpf_local_storage from the *task*.
+ *
+ * 	Logically, it could be thought of as getting the value from
+ * 	a *map* with *task* as the **key**.  From this
+ * 	perspective,  the usage is not much different from
+ * 	**bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
+ * 	helper enforces the key must be a task_struct and the map must also
+ * 	be a **BPF_MAP_TYPE_TASK_STORAGE**.
+ *
+ * 	Underneath, the value is stored locally at *task* instead of
+ * 	the *map*.  The *map* is used as the bpf-local-storage
+ * 	"type". The bpf-local-storage "type" (i.e. the *map*) is
+ * 	searched against all bpf_local_storage residing at *task*.
+ *
+ * 	An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
+ * 	used such that a new bpf_local_storage will be
+ * 	created if one does not exist.  *value* can be used
+ * 	together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
+ * 	the initial value of a bpf_local_storage.  If *value* is
+ * 	**NULL**, the new bpf_local_storage will be zero initialized.
+ *
+ * Returns
+ * 	A bpf_local_storage pointer is returned on success.
+ *
+ * 	**NULL** if not found or there was an error in adding
+ * 	a new bpf_local_storage.
+ */
+static void *(*bpf_task_storage_get)(void *map, struct task_struct *task, void *value, __u64 flags) = (void *) 156;
+
+/*
+ * bpf_task_storage_delete
+ *
+ * 	Delete a bpf_local_storage from a *task*.
+ *
+ * Returns
+ * 	0 on success.
+ *
+ * 	**-ENOENT** if the bpf_local_storage cannot be found.
+ */
+static long (*bpf_task_storage_delete)(void *map, struct task_struct *task) = (void *) 157;
+
+/*
+ * bpf_get_current_task_btf
+ *
+ * 	Return a BTF pointer to the "current" task.
+ * 	This pointer can also be used in helpers that accept an
+ * 	*ARG_PTR_TO_BTF_ID* of type *task_struct*.
+ *
+ * Returns
+ * 	Pointer to the current task.
+ */
+static struct task_struct *(*bpf_get_current_task_btf)(void) = (void *) 158;
+
+/*
+ * bpf_bprm_opts_set
+ *
+ * 	Set or clear certain options on *bprm*:
+ *
+ * 	**BPF_F_BPRM_SECUREEXEC** Set the secureexec bit
+ * 	which sets the **AT_SECURE** auxv for glibc. The bit
+ * 	is cleared if the flag is not specified.
+ *
+ * Returns
+ * 	**-EINVAL** if invalid *flags* are passed, zero otherwise.
+ */
+static long (*bpf_bprm_opts_set)(struct linux_binprm *bprm, __u64 flags) = (void *) 159;
+
+/*
+ * bpf_ktime_get_coarse_ns
+ *
+ * 	Return a coarse-grained version of the time elapsed since
+ * 	system boot, in nanoseconds. Does not include time the system
+ * 	was suspended.
+ *
+ * 	See: **clock_gettime**\ (**CLOCK_MONOTONIC_COARSE**)
+ *
+ * Returns
+ * 	Current *ktime*.
+ */
+static __u64 (*bpf_ktime_get_coarse_ns)(void) = (void *) 160;
+
+/*
+ * bpf_ima_inode_hash
+ *
+ * 	Returns the stored IMA hash of the *inode* (if it's available).
+ * 	If the hash is larger than *size*, then only *size*
+ * 	bytes will be copied to *dst*
+ *
+ * Returns
+ * 	The **hash_algo** is returned on success,
+ * 	**-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
+ * 	invalid arguments are passed.
+ */
+static long (*bpf_ima_inode_hash)(struct inode *inode, void *dst, __u32 size) = (void *) 161;
+
+/*
+ * bpf_sock_from_file
+ *
+ * 	If the given file represents a socket, returns the associated
+ * 	socket.
+ *
+ * Returns
+ * 	A pointer to a struct socket on success or NULL if the file is
+ * 	not a socket.
+ */
+static struct socket *(*bpf_sock_from_file)(struct file *file) = (void *) 162;
+
+/*
+ * bpf_check_mtu
+ *
+ * 	Check packet size against exceeding MTU of net device (based
+ * 	on *ifindex*).  This helper will likely be used in combination
+ * 	with helpers that adjust/change the packet size.
+ *
+ * 	The argument *len_diff* can be used for querying with a planned
+ * 	size change. This allows to check MTU prior to changing packet
+ * 	ctx. Providing a *len_diff* adjustment that is larger than the
+ * 	actual packet size (resulting in negative packet size) will in
+ * 	principle not exceed the MTU, which is why it is not considered
+ * 	a failure.  Other BPF helpers are needed for performing the
+ * 	planned size change; therefore the responsibility for catching
+ * 	a negative packet size belongs in those helpers.
+ *
+ * 	Specifying *ifindex* zero means the MTU check is performed
+ * 	against the current net device.  This is practical if this isn't
+ * 	used prior to redirect.
+ *
+ * 	On input *mtu_len* must be a valid pointer, else verifier will
+ * 	reject BPF program.  If the value *mtu_len* is initialized to
+ * 	zero then the ctx packet size is use.  When value *mtu_len* is
+ * 	provided as input this specify the L3 length that the MTU check
+ * 	is done against. Remember XDP and TC length operate at L2, but
+ * 	this value is L3 as this correlate to MTU and IP-header tot_len
+ * 	values which are L3 (similar behavior as bpf_fib_lookup).
+ *
+ * 	The Linux kernel route table can configure MTUs on a more
+ * 	specific per route level, which is not provided by this helper.
+ * 	For route level MTU checks use the **bpf_fib_lookup**\ ()
+ * 	helper.
+ *
+ * 	*ctx* is either **struct xdp_md** for XDP programs or
+ * 	**struct sk_buff** for tc cls_act programs.
+ *
+ * 	The *flags* argument can be a combination of one or more of the
+ * 	following values:
+ *
+ * 	**BPF_MTU_CHK_SEGS**
+ * 		This flag will only works for *ctx* **struct sk_buff**.
+ * 		If packet context contains extra packet segment buffers
+ * 		(often knows as GSO skb), then MTU check is harder to
+ * 		check at this point, because in transmit path it is
+ * 		possible for the skb packet to get re-segmented
+ * 		(depending on net device features).  This could still be
+ * 		a MTU violation, so this flag enables performing MTU
+ * 		check against segments, with a different violation
+ * 		return code to tell it apart. Check cannot use len_diff.
+ *
+ * 	On return *mtu_len* pointer contains the MTU value of the net
+ * 	device.  Remember the net device configured MTU is the L3 size,
+ * 	which is returned here and XDP and TC length operate at L2.
+ * 	Helper take this into account for you, but remember when using
+ * 	MTU value in your BPF-code.
+ *
+ *
+ * Returns
+ * 	* 0 on success, and populate MTU value in *mtu_len* pointer.
+ *
+ * 	* < 0 if any input argument is invalid (*mtu_len* not updated)
+ *
+ * 	MTU violations return positive values, but also populate MTU
+ * 	value in *mtu_len* pointer, as this can be needed for
+ * 	implementing PMTU handing:
+ *
+ * 	* **BPF_MTU_CHK_RET_FRAG_NEEDED**
+ * 	* **BPF_MTU_CHK_RET_SEGS_TOOBIG**
+ */
+static long (*bpf_check_mtu)(void *ctx, __u32 ifindex, __u32 *mtu_len, __s32 len_diff, __u64 flags) = (void *) 163;
+
+/*
+ * bpf_for_each_map_elem
+ *
+ * 	For each element in **map**, call **callback_fn** function with
+ * 	**map**, **callback_ctx** and other map-specific parameters.
+ * 	The **callback_fn** should be a static function and
+ * 	the **callback_ctx** should be a pointer to the stack.
+ * 	The **flags** is used to control certain aspects of the helper.
+ * 	Currently, the **flags** must be 0.
+ *
+ * 	The following are a list of supported map types and their
+ * 	respective expected callback signatures:
+ *
+ * 	BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_PERCPU_HASH,
+ * 	BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH,
+ * 	BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PERCPU_ARRAY
+ *
+ * 	long (\*callback_fn)(struct bpf_map \*map, const void \*key, void \*value, void \*ctx);
+ *
+ * 	For per_cpu maps, the map_value is the value on the cpu where the
+ * 	bpf_prog is running.
+ *
+ * 	If **callback_fn** return 0, the helper will continue to the next
+ * 	element. If return value is 1, the helper will skip the rest of
+ * 	elements and return. Other return values are not used now.
+ *
+ *
+ * Returns
+ * 	The number of traversed map elements for success, **-EINVAL** for
+ * 	invalid **flags**.
+ */
+static long (*bpf_for_each_map_elem)(void *map, void *callback_fn, void *callback_ctx, __u64 flags) = (void *) 164;
+
+/*
+ * bpf_snprintf
+ *
+ * 	Outputs a string into the **str** buffer of size **str_size**
+ * 	based on a format string stored in a read-only map pointed by
+ * 	**fmt**.
+ *
+ * 	Each format specifier in **fmt** corresponds to one u64 element
+ * 	in the **data** array. For strings and pointers where pointees
+ * 	are accessed, only the pointer values are stored in the *data*
+ * 	array. The *data_len* is the size of *data* in bytes - must be
+ * 	a multiple of 8.
+ *
+ * 	Formats **%s** and **%p{i,I}{4,6}** require to read kernel
+ * 	memory. Reading kernel memory may fail due to either invalid
+ * 	address or valid address but requiring a major memory fault. If
+ * 	reading kernel memory fails, the string for **%s** will be an
+ * 	empty string, and the ip address for **%p{i,I}{4,6}** will be 0.
+ * 	Not returning error to bpf program is consistent with what
+ * 	**bpf_trace_printk**\ () does for now.
+ *
+ *
+ * Returns
+ * 	The strictly positive length of the formatted string, including
+ * 	the trailing zero character. If the return value is greater than
+ * 	**str_size**, **str** contains a truncated string, guaranteed to
+ * 	be zero-terminated except when **str_size** is 0.
+ *
+ * 	Or **-EBUSY** if the per-CPU memory copy buffer is busy.
+ */
+static long (*bpf_snprintf)(char *str, __u32 str_size, const char *fmt, __u64 *data, __u32 data_len) = (void *) 165;
+
+/*
+ * bpf_sys_bpf
+ *
+ * 	Execute bpf syscall with given arguments.
+ *
+ * Returns
+ * 	A syscall result.
+ */
+static long (*bpf_sys_bpf)(__u32 cmd, void *attr, __u32 attr_size) = (void *) 166;
+
+/*
+ * bpf_btf_find_by_name_kind
+ *
+ * 	Find BTF type with given name and kind in vmlinux BTF or in module's BTFs.
+ *
+ * Returns
+ * 	Returns btf_id and btf_obj_fd in lower and upper 32 bits.
+ */
+static long (*bpf_btf_find_by_name_kind)(char *name, int name_sz, __u32 kind, int flags) = (void *) 167;
+
+/*
+ * bpf_sys_close
+ *
+ * 	Execute close syscall for given FD.
+ *
+ * Returns
+ * 	A syscall result.
+ */
+static long (*bpf_sys_close)(__u32 fd) = (void *) 168;
+
+/*
+ * bpf_timer_init
+ *
+ * 	Initialize the timer.
+ * 	First 4 bits of *flags* specify clockid.
+ * 	Only CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME are allowed.
+ * 	All other bits of *flags* are reserved.
+ * 	The verifier will reject the program if *timer* is not from
+ * 	the same *map*.
+ *
+ * Returns
+ * 	0 on success.
+ * 	**-EBUSY** if *timer* is already initialized.
+ * 	**-EINVAL** if invalid *flags* are passed.
+ * 	**-EPERM** if *timer* is in a map that doesn't have any user references.
+ * 	The user space should either hold a file descriptor to a map with timers
+ * 	or pin such map in bpffs. When map is unpinned or file descriptor is
+ * 	closed all timers in the map will be cancelled and freed.
+ */
+static long (*bpf_timer_init)(struct bpf_timer *timer, void *map, __u64 flags) = (void *) 169;
+
+/*
+ * bpf_timer_set_callback
+ *
+ * 	Configure the timer to call *callback_fn* static function.
+ *
+ * Returns
+ * 	0 on success.
+ * 	**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
+ * 	**-EPERM** if *timer* is in a map that doesn't have any user references.
+ * 	The user space should either hold a file descriptor to a map with timers
+ * 	or pin such map in bpffs. When map is unpinned or file descriptor is
+ * 	closed all timers in the map will be cancelled and freed.
+ */
+static long (*bpf_timer_set_callback)(struct bpf_timer *timer, void *callback_fn) = (void *) 170;
+
+/*
+ * bpf_timer_start
+ *
+ * 	Set timer expiration N nanoseconds from the current time. The
+ * 	configured callback will be invoked in soft irq context on some cpu
+ * 	and will not repeat unless another bpf_timer_start() is made.
+ * 	In such case the next invocation can migrate to a different cpu.
+ * 	Since struct bpf_timer is a field inside map element the map
+ * 	owns the timer. The bpf_timer_set_callback() will increment refcnt
+ * 	of BPF program to make sure that callback_fn code stays valid.
+ * 	When user space reference to a map reaches zero all timers
+ * 	in a map are cancelled and corresponding program's refcnts are
+ * 	decremented. This is done to make sure that Ctrl-C of a user
+ * 	process doesn't leave any timers running. If map is pinned in
+ * 	bpffs the callback_fn can re-arm itself indefinitely.
+ * 	bpf_map_update/delete_elem() helpers and user space sys_bpf commands
+ * 	cancel and free the timer in the given map element.
+ * 	The map can contain timers that invoke callback_fn-s from different
+ * 	programs. The same callback_fn can serve different timers from
+ * 	different maps if key/value layout matches across maps.
+ * 	Every bpf_timer_set_callback() can have different callback_fn.
+ *
+ *
+ * Returns
+ * 	0 on success.
+ * 	**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier
+ * 	or invalid *flags* are passed.
+ */
+static long (*bpf_timer_start)(struct bpf_timer *timer, __u64 nsecs, __u64 flags) = (void *) 171;
+
+/*
+ * bpf_timer_cancel
+ *
+ * 	Cancel the timer and wait for callback_fn to finish if it was running.
+ *
+ * Returns
+ * 	0 if the timer was not active.
+ * 	1 if the timer was active.
+ * 	**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
+ * 	**-EDEADLK** if callback_fn tried to call bpf_timer_cancel() on its
+ * 	own timer which would have led to a deadlock otherwise.
+ */
+static long (*bpf_timer_cancel)(struct bpf_timer *timer) = (void *) 172;
+
+/*
+ * bpf_get_func_ip
+ *
+ * 	Get address of the traced function (for tracing and kprobe programs).
+ *
+ * Returns
+ * 	Address of the traced function.
+ * 	0 for kprobes placed within the function (not at the entry).
+ */
+static __u64 (*bpf_get_func_ip)(void *ctx) = (void *) 173;
+
+/*
+ * bpf_get_attach_cookie
+ *
+ * 	Get bpf_cookie value provided (optionally) during the program
+ * 	attachment. It might be different for each individual
+ * 	attachment, even if BPF program itself is the same.
+ * 	Expects BPF program context *ctx* as a first argument.
+ *
+ * 	Supported for the following program types:
+ * 		- kprobe/uprobe;
+ * 		- tracepoint;
+ * 		- perf_event.
+ *
+ * Returns
+ * 	Value specified by user at BPF link creation/attachment time
+ * 	or 0, if it was not specified.
+ */
+static __u64 (*bpf_get_attach_cookie)(void *ctx) = (void *) 174;
+
+/*
+ * bpf_task_pt_regs
+ *
+ * 	Get the struct pt_regs associated with **task**.
+ *
+ * Returns
+ * 	A pointer to struct pt_regs.
+ */
+static long (*bpf_task_pt_regs)(struct task_struct *task) = (void *) 175;
+
+/*
+ * bpf_get_branch_snapshot
+ *
+ * 	Get branch trace from hardware engines like Intel LBR. The
+ * 	hardware engine is stopped shortly after the helper is
+ * 	called. Therefore, the user need to filter branch entries
+ * 	based on the actual use case. To capture branch trace
+ * 	before the trigger point of the BPF program, the helper
+ * 	should be called at the beginning of the BPF program.
+ *
+ * 	The data is stored as struct perf_branch_entry into output
+ * 	buffer *entries*. *size* is the size of *entries* in bytes.
+ * 	*flags* is reserved for now and must be zero.
+ *
+ *
+ * Returns
+ * 	On success, number of bytes written to *buf*. On error, a
+ * 	negative value.
+ *
+ * 	**-EINVAL** if *flags* is not zero.
+ *
+ * 	**-ENOENT** if architecture does not support branch records.
+ */
+static long (*bpf_get_branch_snapshot)(void *entries, __u32 size, __u64 flags) = (void *) 176;
+
+/*
+ * bpf_trace_vprintk
+ *
+ * 	Behaves like **bpf_trace_printk**\ () helper, but takes an array of u64
+ * 	to format and can handle more format args as a result.
+ *
+ * 	Arguments are to be used as in **bpf_seq_printf**\ () helper.
+ *
+ * Returns
+ * 	The number of bytes written to the buffer, or a negative error
+ * 	in case of failure.
+ */
+static long (*bpf_trace_vprintk)(const char *fmt, __u32 fmt_size, const void *data, __u32 data_len) = (void *) 177;
+
+/*
+ * bpf_skc_to_unix_sock
+ *
+ * 	Dynamically cast a *sk* pointer to a *unix_sock* pointer.
+ *
+ * Returns
+ * 	*sk* if casting is valid, or **NULL** otherwise.
+ */
+static struct unix_sock *(*bpf_skc_to_unix_sock)(void *sk) = (void *) 178;
+
+/*
+ * bpf_kallsyms_lookup_name
+ *
+ * 	Get the address of a kernel symbol, returned in *res*. *res* is
+ * 	set to 0 if the symbol is not found.
+ *
+ * Returns
+ * 	On success, zero. On error, a negative value.
+ *
+ * 	**-EINVAL** if *flags* is not zero.
+ *
+ * 	**-EINVAL** if string *name* is not the same size as *name_sz*.
+ *
+ * 	**-ENOENT** if symbol is not found.
+ *
+ * 	**-EPERM** if caller does not have permission to obtain kernel address.
+ */
+static long (*bpf_kallsyms_lookup_name)(const char *name, int name_sz, int flags, __u64 *res) = (void *) 179;
+
+/*
+ * bpf_find_vma
+ *
+ * 	Find vma of *task* that contains *addr*, call *callback_fn*
+ * 	function with *task*, *vma*, and *callback_ctx*.
+ * 	The *callback_fn* should be a static function and
+ * 	the *callback_ctx* should be a pointer to the stack.
+ * 	The *flags* is used to control certain aspects of the helper.
+ * 	Currently, the *flags* must be 0.
+ *
+ * 	The expected callback signature is
+ *
+ * 	long (\*callback_fn)(struct task_struct \*task, struct vm_area_struct \*vma, void \*callback_ctx);
+ *
+ *
+ * Returns
+ * 	0 on success.
+ * 	**-ENOENT** if *task->mm* is NULL, or no vma contains *addr*.
+ * 	**-EBUSY** if failed to try lock mmap_lock.
+ * 	**-EINVAL** for invalid **flags**.
+ */
+static long (*bpf_find_vma)(struct task_struct *task, __u64 addr, void *callback_fn, void *callback_ctx, __u64 flags) = (void *) 180;
+
+/*
+ * bpf_loop
+ *
+ * 	For **nr_loops**, call **callback_fn** function
+ * 	with **callback_ctx** as the context parameter.
+ * 	The **callback_fn** should be a static function and
+ * 	the **callback_ctx** should be a pointer to the stack.
+ * 	The **flags** is used to control certain aspects of the helper.
+ * 	Currently, the **flags** must be 0. Currently, nr_loops is
+ * 	limited to 1 << 23 (~8 million) loops.
+ *
+ * 	long (\*callback_fn)(u32 index, void \*ctx);
+ *
+ * 	where **index** is the current index in the loop. The index
+ * 	is zero-indexed.
+ *
+ * 	If **callback_fn** returns 0, the helper will continue to the next
+ * 	loop. If return value is 1, the helper will skip the rest of
+ * 	the loops and return. Other return values are not used now,
+ * 	and will be rejected by the verifier.
+ *
+ *
+ * Returns
+ * 	The number of loops performed, **-EINVAL** for invalid **flags**,
+ * 	**-E2BIG** if **nr_loops** exceeds the maximum number of loops.
+ */
+static long (*bpf_loop)(__u32 nr_loops, void *callback_fn, void *callback_ctx, __u64 flags) = (void *) 181;
+
+/*
+ * bpf_strncmp
+ *
+ * 	Do strncmp() between **s1** and **s2**. **s1** doesn't need
+ * 	to be null-terminated and **s1_sz** is the maximum storage
+ * 	size of **s1**. **s2** must be a read-only string.
+ *
+ * Returns
+ * 	An integer less than, equal to, or greater than zero
+ * 	if the first **s1_sz** bytes of **s1** is found to be
+ * 	less than, to match, or be greater than **s2**.
+ */
+static long (*bpf_strncmp)(const char *s1, __u32 s1_sz, const char *s2) = (void *) 182;
+
+/*
+ * bpf_get_func_arg
+ *
+ * 	Get **n**-th argument register (zero based) of the traced function (for tracing programs)
+ * 	returned in **value**.
+ *
+ *
+ * Returns
+ * 	0 on success.
+ * 	**-EINVAL** if n >= argument register count of traced function.
+ */
+static long (*bpf_get_func_arg)(void *ctx, __u32 n, __u64 *value) = (void *) 183;
+
+/*
+ * bpf_get_func_ret
+ *
+ * 	Get return value of the traced function (for tracing programs)
+ * 	in **value**.
+ *
+ *
+ * Returns
+ * 	0 on success.
+ * 	**-EOPNOTSUPP** for tracing programs other than BPF_TRACE_FEXIT or BPF_MODIFY_RETURN.
+ */
+static long (*bpf_get_func_ret)(void *ctx, __u64 *value) = (void *) 184;
+
+/*
+ * bpf_get_func_arg_cnt
+ *
+ * 	Get number of registers of the traced function (for tracing programs) where
+ * 	function arguments are stored in these registers.
+ *
+ *
+ * Returns
+ * 	The number of argument registers of the traced function.
+ */
+static long (*bpf_get_func_arg_cnt)(void *ctx) = (void *) 185;
+
+/*
+ * bpf_get_retval
+ *
+ * 	Get the BPF program's return value that will be returned to the upper layers.
+ *
+ * 	This helper is currently supported by cgroup programs and only by the hooks
+ * 	where BPF program's return value is returned to the userspace via errno.
+ *
+ * Returns
+ * 	The BPF program's return value.
+ */
+static int (*bpf_get_retval)(void) = (void *) 186;
+
+/*
+ * bpf_set_retval
+ *
+ * 	Set the BPF program's return value that will be returned to the upper layers.
+ *
+ * 	This helper is currently supported by cgroup programs and only by the hooks
+ * 	where BPF program's return value is returned to the userspace via errno.
+ *
+ * 	Note that there is the following corner case where the program exports an error
+ * 	via bpf_set_retval but signals success via 'return 1':
+ *
+ * 		bpf_set_retval(-EPERM);
+ * 		return 1;
+ *
+ * 	In this case, the BPF program's return value will use helper's -EPERM. This
+ * 	still holds true for cgroup/bind{4,6} which supports extra 'return 3' success case.
+ *
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static int (*bpf_set_retval)(int retval) = (void *) 187;
+
+/*
+ * bpf_xdp_get_buff_len
+ *
+ * 	Get the total size of a given xdp buff (linear and paged area)
+ *
+ * Returns
+ * 	The total size of a given xdp buffer.
+ */
+static __u64 (*bpf_xdp_get_buff_len)(struct xdp_md *xdp_md) = (void *) 188;
+
+/*
+ * bpf_xdp_load_bytes
+ *
+ * 	This helper is provided as an easy way to load data from a
+ * 	xdp buffer. It can be used to load *len* bytes from *offset* from
+ * 	the frame associated to *xdp_md*, into the buffer pointed by
+ * 	*buf*.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_xdp_load_bytes)(struct xdp_md *xdp_md, __u32 offset, void *buf, __u32 len) = (void *) 189;
+
+/*
+ * bpf_xdp_store_bytes
+ *
+ * 	Store *len* bytes from buffer *buf* into the frame
+ * 	associated to *xdp_md*, at *offset*.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_xdp_store_bytes)(struct xdp_md *xdp_md, __u32 offset, void *buf, __u32 len) = (void *) 190;
+
+/*
+ * bpf_copy_from_user_task
+ *
+ * 	Read *size* bytes from user space address *user_ptr* in *tsk*'s
+ * 	address space, and stores the data in *dst*. *flags* is not
+ * 	used yet and is provided for future extensibility. This helper
+ * 	can only be used by sleepable programs.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure. On error
+ * 	*dst* buffer is zeroed out.
+ */
+static long (*bpf_copy_from_user_task)(void *dst, __u32 size, const void *user_ptr, struct task_struct *tsk, __u64 flags) = (void *) 191;
+
+/*
+ * bpf_skb_set_tstamp
+ *
+ * 	Change the __sk_buff->tstamp_type to *tstamp_type*
+ * 	and set *tstamp* to the __sk_buff->tstamp together.
+ *
+ * 	If there is no need to change the __sk_buff->tstamp_type,
+ * 	the tstamp value can be directly written to __sk_buff->tstamp
+ * 	instead.
+ *
+ * 	BPF_SKB_TSTAMP_DELIVERY_MONO is the only tstamp that
+ * 	will be kept during bpf_redirect_*().  A non zero
+ * 	*tstamp* must be used with the BPF_SKB_TSTAMP_DELIVERY_MONO
+ * 	*tstamp_type*.
+ *
+ * 	A BPF_SKB_TSTAMP_UNSPEC *tstamp_type* can only be used
+ * 	with a zero *tstamp*.
+ *
+ * 	Only IPv4 and IPv6 skb->protocol are supported.
+ *
+ * 	This function is most useful when it needs to set a
+ * 	mono delivery time to __sk_buff->tstamp and then
+ * 	bpf_redirect_*() to the egress of an iface.  For example,
+ * 	changing the (rcv) timestamp in __sk_buff->tstamp at
+ * 	ingress to a mono delivery time and then bpf_redirect_*()
+ * 	to sch_fq@phy-dev.
+ *
+ * Returns
+ * 	0 on success.
+ * 	**-EINVAL** for invalid input
+ * 	**-EOPNOTSUPP** for unsupported protocol
+ */
+static long (*bpf_skb_set_tstamp)(struct __sk_buff *skb, __u64 tstamp, __u32 tstamp_type) = (void *) 192;
+
+/*
+ * bpf_ima_file_hash
+ *
+ * 	Returns a calculated IMA hash of the *file*.
+ * 	If the hash is larger than *size*, then only *size*
+ * 	bytes will be copied to *dst*
+ *
+ * Returns
+ * 	The **hash_algo** is returned on success,
+ * 	**-EOPNOTSUP** if the hash calculation failed or **-EINVAL** if
+ * 	invalid arguments are passed.
+ */
+static long (*bpf_ima_file_hash)(struct file *file, void *dst, __u32 size) = (void *) 193;
+
+/*
+ * bpf_kptr_xchg
+ *
+ * 	Exchange kptr at pointer *map_value* with *ptr*, and return the
+ * 	old value. *ptr* can be NULL, otherwise it must be a referenced
+ * 	pointer which will be released when this helper is called.
+ *
+ * Returns
+ * 	The old value of kptr (which can be NULL). The returned pointer
+ * 	if not NULL, is a reference which must be released using its
+ * 	corresponding release function, or moved into a BPF map before
+ * 	program exit.
+ */
+static void *(*bpf_kptr_xchg)(void *map_value, void *ptr) = (void *) 194;
+
+/*
+ * bpf_map_lookup_percpu_elem
+ *
+ * 	Perform a lookup in *percpu map* for an entry associated to
+ * 	*key* on *cpu*.
+ *
+ * Returns
+ * 	Map value associated to *key* on *cpu*, or **NULL** if no entry
+ * 	was found or *cpu* is invalid.
+ */
+static void *(*bpf_map_lookup_percpu_elem)(void *map, const void *key, __u32 cpu) = (void *) 195;
+
+/*
+ * bpf_skc_to_mptcp_sock
+ *
+ * 	Dynamically cast a *sk* pointer to a *mptcp_sock* pointer.
+ *
+ * Returns
+ * 	*sk* if casting is valid, or **NULL** otherwise.
+ */
+static struct mptcp_sock *(*bpf_skc_to_mptcp_sock)(void *sk) = (void *) 196;
+
+/*
+ * bpf_dynptr_from_mem
+ *
+ * 	Get a dynptr to local memory *data*.
+ *
+ * 	*data* must be a ptr to a map value.
+ * 	The maximum *size* supported is DYNPTR_MAX_SIZE.
+ * 	*flags* is currently unused.
+ *
+ * Returns
+ * 	0 on success, -E2BIG if the size exceeds DYNPTR_MAX_SIZE,
+ * 	-EINVAL if flags is not 0.
+ */
+static long (*bpf_dynptr_from_mem)(void *data, __u32 size, __u64 flags, struct bpf_dynptr *ptr) = (void *) 197;
+
+/*
+ * bpf_ringbuf_reserve_dynptr
+ *
+ * 	Reserve *size* bytes of payload in a ring buffer *ringbuf*
+ * 	through the dynptr interface. *flags* must be 0.
+ *
+ * 	Please note that a corresponding bpf_ringbuf_submit_dynptr or
+ * 	bpf_ringbuf_discard_dynptr must be called on *ptr*, even if the
+ * 	reservation fails. This is enforced by the verifier.
+ *
+ * Returns
+ * 	0 on success, or a negative error in case of failure.
+ */
+static long (*bpf_ringbuf_reserve_dynptr)(void *ringbuf, __u32 size, __u64 flags, struct bpf_dynptr *ptr) = (void *) 198;
+
+/*
+ * bpf_ringbuf_submit_dynptr
+ *
+ * 	Submit reserved ring buffer sample, pointed to by *data*,
+ * 	through the dynptr interface. This is a no-op if the dynptr is
+ * 	invalid/null.
+ *
+ * 	For more information on *flags*, please see
+ * 	'bpf_ringbuf_submit'.
+ *
+ * Returns
+ * 	Nothing. Always succeeds.
+ */
+static void (*bpf_ringbuf_submit_dynptr)(struct bpf_dynptr *ptr, __u64 flags) = (void *) 199;
+
+/*
+ * bpf_ringbuf_discard_dynptr
+ *
+ * 	Discard reserved ring buffer sample through the dynptr
+ * 	interface. This is a no-op if the dynptr is invalid/null.
+ *
+ * 	For more information on *flags*, please see
+ * 	'bpf_ringbuf_discard'.
+ *
+ * Returns
+ * 	Nothing. Always succeeds.
+ */
+static void (*bpf_ringbuf_discard_dynptr)(struct bpf_dynptr *ptr, __u64 flags) = (void *) 200;
+
+/*
+ * bpf_dynptr_read
+ *
+ * 	Read *len* bytes from *src* into *dst*, starting from *offset*
+ * 	into *src*.
+ * 	*flags* is currently unused.
+ *
+ * Returns
+ * 	0 on success, -E2BIG if *offset* + *len* exceeds the length
+ * 	of *src*'s data, -EINVAL if *src* is an invalid dynptr or if
+ * 	*flags* is not 0.
+ */
+static long (*bpf_dynptr_read)(void *dst, __u32 len, const struct bpf_dynptr *src, __u32 offset, __u64 flags) = (void *) 201;
+
+/*
+ * bpf_dynptr_write
+ *
+ * 	Write *len* bytes from *src* into *dst*, starting from *offset*
+ * 	into *dst*.
+ * 	*flags* is currently unused.
+ *
+ * Returns
+ * 	0 on success, -E2BIG if *offset* + *len* exceeds the length
+ * 	of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst*
+ * 	is a read-only dynptr or if *flags* is not 0.
+ */
+static long (*bpf_dynptr_write)(const struct bpf_dynptr *dst, __u32 offset, void *src, __u32 len, __u64 flags) = (void *) 202;
+
+/*
+ * bpf_dynptr_data
+ *
+ * 	Get a pointer to the underlying dynptr data.
+ *
+ * 	*len* must be a statically known value. The returned data slice
+ * 	is invalidated whenever the dynptr is invalidated.
+ *
+ * Returns
+ * 	Pointer to the underlying dynptr data, NULL if the dynptr is
+ * 	read-only, if the dynptr is invalid, or if the offset and length
+ * 	is out of bounds.
+ */
+static void *(*bpf_dynptr_data)(const struct bpf_dynptr *ptr, __u32 offset, __u32 len) = (void *) 203;
+
+/*
+ * bpf_tcp_raw_gen_syncookie_ipv4
+ *
+ * 	Try to issue a SYN cookie for the packet with corresponding
+ * 	IPv4/TCP headers, *iph* and *th*, without depending on a
+ * 	listening socket.
+ *
+ * 	*iph* points to the IPv4 header.
+ *
+ * 	*th* points to the start of the TCP header, while *th_len*
+ * 	contains the length of the TCP header (at least
+ * 	**sizeof**\ (**struct tcphdr**)).
+ *
+ * Returns
+ * 	On success, lower 32 bits hold the generated SYN cookie in
+ * 	followed by 16 bits which hold the MSS value for that cookie,
+ * 	and the top 16 bits are unused.
+ *
+ * 	On failure, the returned value is one of the following:
+ *
+ * 	**-EINVAL** if *th_len* is invalid.
+ */
+static __s64 (*bpf_tcp_raw_gen_syncookie_ipv4)(struct iphdr *iph, struct tcphdr *th, __u32 th_len) = (void *) 204;
+
+/*
+ * bpf_tcp_raw_gen_syncookie_ipv6
+ *
+ * 	Try to issue a SYN cookie for the packet with corresponding
+ * 	IPv6/TCP headers, *iph* and *th*, without depending on a
+ * 	listening socket.
+ *
+ * 	*iph* points to the IPv6 header.
+ *
+ * 	*th* points to the start of the TCP header, while *th_len*
+ * 	contains the length of the TCP header (at least
+ * 	**sizeof**\ (**struct tcphdr**)).
+ *
+ * Returns
+ * 	On success, lower 32 bits hold the generated SYN cookie in
+ * 	followed by 16 bits which hold the MSS value for that cookie,
+ * 	and the top 16 bits are unused.
+ *
+ * 	On failure, the returned value is one of the following:
+ *
+ * 	**-EINVAL** if *th_len* is invalid.
+ *
+ * 	**-EPROTONOSUPPORT** if CONFIG_IPV6 is not builtin.
+ */
+static __s64 (*bpf_tcp_raw_gen_syncookie_ipv6)(struct ipv6hdr *iph, struct tcphdr *th, __u32 th_len) = (void *) 205;
+
+/*
+ * bpf_tcp_raw_check_syncookie_ipv4
+ *
+ * 	Check whether *iph* and *th* contain a valid SYN cookie ACK
+ * 	without depending on a listening socket.
+ *
+ * 	*iph* points to the IPv4 header.
+ *
+ * 	*th* points to the TCP header.
+ *
+ * Returns
+ * 	0 if *iph* and *th* are a valid SYN cookie ACK.
+ *
+ * 	On failure, the returned value is one of the following:
+ *
+ * 	**-EACCES** if the SYN cookie is not valid.
+ */
+static long (*bpf_tcp_raw_check_syncookie_ipv4)(struct iphdr *iph, struct tcphdr *th) = (void *) 206;
+
+/*
+ * bpf_tcp_raw_check_syncookie_ipv6
+ *
+ * 	Check whether *iph* and *th* contain a valid SYN cookie ACK
+ * 	without depending on a listening socket.
+ *
+ * 	*iph* points to the IPv6 header.
+ *
+ * 	*th* points to the TCP header.
+ *
+ * Returns
+ * 	0 if *iph* and *th* are a valid SYN cookie ACK.
+ *
+ * 	On failure, the returned value is one of the following:
+ *
+ * 	**-EACCES** if the SYN cookie is not valid.
+ *
+ * 	**-EPROTONOSUPPORT** if CONFIG_IPV6 is not builtin.
+ */
+static long (*bpf_tcp_raw_check_syncookie_ipv6)(struct ipv6hdr *iph, struct tcphdr *th) = (void *) 207;
+
+/*
+ * bpf_ktime_get_tai_ns
+ *
+ * 	A nonsettable system-wide clock derived from wall-clock time but
+ * 	ignoring leap seconds.  This clock does not experience
+ * 	discontinuities and backwards jumps caused by NTP inserting leap
+ * 	seconds as CLOCK_REALTIME does.
+ *
+ * 	See: **clock_gettime**\ (**CLOCK_TAI**)
+ *
+ * Returns
+ * 	Current *ktime*.
+ */
+static __u64 (*bpf_ktime_get_tai_ns)(void) = (void *) 208;
+
+/*
+ * bpf_user_ringbuf_drain
+ *
+ * 	Drain samples from the specified user ring buffer, and invoke
+ * 	the provided callback for each such sample:
+ *
+ * 	long (\*callback_fn)(const struct bpf_dynptr \*dynptr, void \*ctx);
+ *
+ * 	If **callback_fn** returns 0, the helper will continue to try
+ * 	and drain the next sample, up to a maximum of
+ * 	BPF_MAX_USER_RINGBUF_SAMPLES samples. If the return value is 1,
+ * 	the helper will skip the rest of the samples and return. Other
+ * 	return values are not used now, and will be rejected by the
+ * 	verifier.
+ *
+ * Returns
+ * 	The number of drained samples if no error was encountered while
+ * 	draining samples, or 0 if no samples were present in the ring
+ * 	buffer. If a user-space producer was epoll-waiting on this map,
+ * 	and at least one sample was drained, they will receive an event
+ * 	notification notifying them of available space in the ring
+ * 	buffer. If the BPF_RB_NO_WAKEUP flag is passed to this
+ * 	function, no wakeup notification will be sent. If the
+ * 	BPF_RB_FORCE_WAKEUP flag is passed, a wakeup notification will
+ * 	be sent even if no sample was drained.
+ *
+ * 	On failure, the returned value is one of the following:
+ *
+ * 	**-EBUSY** if the ring buffer is contended, and another calling
+ * 	context was concurrently draining the ring buffer.
+ *
+ * 	**-EINVAL** if user-space is not properly tracking the ring
+ * 	buffer due to the producer position not being aligned to 8
+ * 	bytes, a sample not being aligned to 8 bytes, or the producer
+ * 	position not matching the advertised length of a sample.
+ *
+ * 	**-E2BIG** if user-space has tried to publish a sample which is
+ * 	larger than the size of the ring buffer, or which cannot fit
+ * 	within a struct bpf_dynptr.
+ */
+static long (*bpf_user_ringbuf_drain)(void *map, void *callback_fn, void *ctx, __u64 flags) = (void *) 209;
+
+/*
+ * bpf_cgrp_storage_get
+ *
+ * 	Get a bpf_local_storage from the *cgroup*.
+ *
+ * 	Logically, it could be thought of as getting the value from
+ * 	a *map* with *cgroup* as the **key**.  From this
+ * 	perspective,  the usage is not much different from
+ * 	**bpf_map_lookup_elem**\ (*map*, **&**\ *cgroup*) except this
+ * 	helper enforces the key must be a cgroup struct and the map must also
+ * 	be a **BPF_MAP_TYPE_CGRP_STORAGE**.
+ *
+ * 	In reality, the local-storage value is embedded directly inside of the
+ * 	*cgroup* object itself, rather than being located in the
+ * 	**BPF_MAP_TYPE_CGRP_STORAGE** map. When the local-storage value is
+ * 	queried for some *map* on a *cgroup* object, the kernel will perform an
+ * 	O(n) iteration over all of the live local-storage values for that
+ * 	*cgroup* object until the local-storage value for the *map* is found.
+ *
+ * 	An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
+ * 	used such that a new bpf_local_storage will be
+ * 	created if one does not exist.  *value* can be used
+ * 	together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
+ * 	the initial value of a bpf_local_storage.  If *value* is
+ * 	**NULL**, the new bpf_local_storage will be zero initialized.
+ *
+ * Returns
+ * 	A bpf_local_storage pointer is returned on success.
+ *
+ * 	**NULL** if not found or there was an error in adding
+ * 	a new bpf_local_storage.
+ */
+static void *(*bpf_cgrp_storage_get)(void *map, struct cgroup *cgroup, void *value, __u64 flags) = (void *) 210;
+
+/*
+ * bpf_cgrp_storage_delete
+ *
+ * 	Delete a bpf_local_storage from a *cgroup*.
+ *
+ * Returns
+ * 	0 on success.
+ *
+ * 	**-ENOENT** if the bpf_local_storage cannot be found.
+ */
+static long (*bpf_cgrp_storage_delete)(void *map, struct cgroup *cgroup) = (void *) 211;
+
+